Timeline History of 20th Century Classical Music

Note: This is an "old" page, now superceded by this page:
Timeline History of 20th Century Classical and Electronic Music

      The below timeline of contemporary classical music (1903-1988) was first inspired from Paul Griffiths' excellent book "Modern Music A Concise History". I added many other entries based on various other sources (see link at bottom) and personal taste. More detail on the works of Karlheinz Stockhausen can be found here.
      To look for a specific year, composer, or work, use "Control-F" (find) and "Control-G" (find next) to fast navigate. Also, every entry is formatted so that you can highlight a composer/work and right click on it to open a menu which will allow you to do a quick Google/Bing search (taking you to a YouTube clip, etc...).
-----


Richard Wagner's "Tristan and Isolde" (1865) pushes harmony outside of diatonic keys.
Richard Strauss: "Also sprach Zarathustra", "Ein Heldenleben" (addresses the problem of form with symphonic poems, and by painting narratives)
Gustav Mahler writes symphonies which are based on psychological confessions (but mostly diatonic), and uses dynamics to shape form structure.  He uses exotic instruments to create a more worldly atmosphere.
Percy Grainger conceives of "Free Music" which is not constrained by Western tuning or rhythmic meter.
1894 Claude Debussy: "Prelude a L'apres-midi d'un faune" (premiere): uses free harmony leading to multiple keys, form is free (theme is embellished as a fragments in an improvisation), orchestration (coloring) is an integral element to the work
1899 Arnold Schoenberg: "Verklärte Nacht" ("Transfigured Night", chromatic but still uses classical form)
1900 Schoenberg begins "Gurre-Lieder", still basically influenced by Wagner and Romantic style.  In 1903 Mahler's music would influence additional sections
1902 Debussy: "Pelléas et Mélisande"
1903 Debussy's "Pagodes" uses oriental scales and rhythms
Maurice Ravel's String Quartet uses odd time signatures (5/8 in the last movement)
Erik Satie: "Three Pieces in the Shape of a Pear"  
1904 Béla Bartók first begins transcribing folk songs (and continues for the next 15 years) in Hungary, N. Africa and Turkey.  Though initially influenced by R. Strauss and Debussy, these studies eventually provide Bartók with an alternative way out of traditional harmony than Schoenberg's later mathematical approach (using church modes, pentatonic scales, etc..., enigmatic rhythm changes).
1905 Debussy: "La Mer" (premiere)
Max Reger and Ferruccio Busoni address chromaticism through Baroque counterpoint.  
Many composers during the following century continue the tonal music tradition in the guise of Neo-Romanticism: Edward Elgar (1857-1934), Frederick Delius (1862-1934), Sergei Rachmaninoff (1873-1943), Hans Pfitzner (1869-1949), Jean Sibelius (1865-1957), William Walton (1902-83), Samuel Barber (1910-81), Hans Werner Henze (also integrating atonality and jazz, 1926-2012), etc...
1906 Schoenberg's "Chamber Symphony No. 1" uses harmony based on 4ths instead of the traditional major/minor 3rds.
Charles Ives: "Central Park in the Dark" (a sound portrait designed to evoke an environment from the past)
1907 Ravel: "L'heure espagnole" opera, uses Spanish imagery
"Sketch Of A New Aesthetic Of Music" published by Busoni
1908 Schoenberg 2nd String Quartet: Schoenberg is finally forced to fully embraces atonality in the final 2 movements of the 2nd String Quartet (soprano sings, "I breathe the air of other planets..." in previous movement) and the "Book of the Hanging Gardens" (using lyric form).  Other composers at this time, such as Mahler, Sibelius, Strauss, and Scriabin, approach atonality, but never make the leap.  Other composers do write atonally, but are not directly influenced by Schoenberg (Varèse, Ives, Cowell, Ruggles, Nikolay Roslavets, etc...)
Schoenberg: "Book of the Hanging Gardens" (uses lyric form).  
Debussy: "Golliwogg's Cakewalk" from "Children's Corner" uses elements from jazz ragtime. 
Bartók: "14 Bagatelles" are influenced by Debussy, leading him away from his earlier Straussian (Romantic) background
1909 Schoenberg: "Three Piano Pieces, Op. 11", uses dramatic form (classical/epic form) with atonality
Schoenberg: "Five Orchestral Pieces Op. 16" (3rd movement "Klangfarbenmelodie" creates a "sound color melody" by orchestrating slow shifting chords with  different instruments, but not much harmonic motion)
Schoenberg: "Erwartung"
Anton Webern: "5 Lieder from "Der siebente Ring" by S. George, op. 3", follows Schoenberg into atonality with 14 songs based on poems of Stefan George
Bartók : String Quartet 1 
Strauss: "Elektra" opera
1910 Webern's 6 Orchestral Pieces, Op.6 - influenced by both Schoenberg and Mahler
Alban Berg: "Vier Lieder", Op. 2 (also approaches extreme chromaticism)
Igor Stravinsky: "The Firebird"
Alexander Scriabin's "Prometheus: The Poem of Fire" uses his "mystic chord" and is accompanied by a "color organ"
Scott Joplin: "Treemonisha" (opera which uses folk and ragtime as elements) 
1911 Schoenberg: "Gurre lieder" continued (chromatic, using lyric form)
Bartók's "Duke Bluebeard's Castle" uses Straussian orchestration but Hungarian melodies and rhythms, ballad form
Stravinsky's "Petrushka" uses polytonality (more than 1 key at once, C and F# Major), later Darius Milhaud uses a similar technique
Ravel's "Daphne et Chloe" ballet uses imagery from classical Greece
In "Pierrot lunaire", Schoenberg notates pitches for a soprano using sprechstimme ("speech-song"), where notes are immediately abandoned as they rise or fall away.  It is written with a "light, ironic satirical tone" to show that atonal music was not all "disturbing feelings" (tho it still has elements of isolation, violence, glee and nostalgia).  The form revisits counterpoint.
Bartók: "Allegro Barbaro" uses folk elements but in a driving propulsive solo piano work
1912 Henry Cowell: "The Tides of Manaunaun", uses piano clusters for the 1st time
Debussy: "Préludes, Book 2" (completed 1913).  Debussy continues to explore harmony using exotic modes and scales, making his atonality hidden
Percy Grainger's "Random Round" (begun 1912) explores indeterminate form.
1913 Debussy: "Jeux" - abandons classical form with sudden, continuous change (total emancipation from consecutive development.  This evolution first began in" Prelude a L'apres-midi d'un faune" and "La Mer's" "Jeux de vagues")
Stravinsky: "Rite of Spring" - explores advanced rhythm (folk-inspired "additive rhythm"), free meter, cell structures, etc…  uses diatonic folk music as melodic basis
Webern's "6 Bagatelles for String Quartet", atonal, concise, haiku-like.  Breaths of sound or subtle ostinatos tend towards timelessness (opposite of Stravinsky's rhythmic motifs)
Webern: 5 Orchesterstücke
1914 Ives' "Three Places in New England" (begun 1911, sketches from 1903), features collaged genre elements (marches, popular songs, dance music and hymns, particularly the 2nd movement, "Putnam's Camp, Redding, Connecticut" which includes "Yankee Doodle", "The British Grenadiers" and John Philip Sousa's march "Semper Fidelis").
Luigi Russolo: "Intonarumori Music", exhibits his "noise machines" in London.
Satie: "Sports et Divertissements"
World War I begins
1915 Berg's "3 Orchestral Pieces" - chromatic, but in between Schoenberg and Mahler
Microtonal music begins to be explored by Alois Hába ("Suite for String Orchestra", 1917), Charles Ives ("Three Quarter Tone Pieces for Two Pianos", 1923-24), Alban Berg ("Chamber Concerto, 1925), Julian Carrillo ("Bosquejos for String Quartet", 1926), Ivan Vishnegradsky, Aaron Copland (Vitebsk, 1929), Bartok (Violin Concerto 2, 1937), etc...
Ives' "Concord Sonata" (begun 1911)
Manual de Falla: "Nights in the Gardens of Spain", influenced by Debussy and Paris
Stravinsky's "Renard" uses Russian folk as an inspiration ("burlesque in song and dance")
Zoltán Kodály: "Sonata for Solo Cello, Op. 8" (blends Hungarian folk elements with modern instrumental technique - uses scordatura, ie - alternate tunings)
1916 Leoš Janáček: "Jenůfa", opera drawing from Czech folk music and Moravian speech rhythms (much like Bartók with Hungarian folk music)
Gustav Holst: "The Planets" (begun 1914)
1917 Bartók: String Quartet 2
Satie's "Furniture Music" (Dadaist influence)
Satie: "Parade" (ballet)
Sergei Prokofiev's Symphony No. 1, the "Classical Symphony" foreshadows Neoclassicism
Bartók: "The Wooden Prince" ballet
1918 Bartók: "The Miraculous Mandarin" (completed 1925), influenced by the "Rite of Spring" (as well as Schoenberg and Strauss)
World War I ends
Stravinsky: "The Soldier's Tale", originating from Russian folk stories, includes parodies of popular dance forms (ragtime, tango).  
Stravinsky: "Rag-Time" and "Piano-rag-music".  These tendencies will eventually lead to Neoclassicism.
Death of Claude Debussy.
1919 de Falla:  "The Three-Cornered Hat", returning to Spain, de Falla finds his own (Spanish folk) voice, but still with some influence from Stravinsky)
Prokofiev's "The Love for Three Oranges" has elements of Neoclassicism (musical satires)
Francis Poulenc: "Cocardes", sets Jean Cocteau's words to music in a song cycle
Edward Elgar's "Cello Concerto"
Ravel's "Le Tombeau de Couperin" approaches Neoclassicism, based on a French Baroque suite.  His later works are further influenced by Neoclassicism.
Cowell: "Quartet Euphometric" (begun 1916, expresses frequencies as rhythms) 
Erwin Schulhoff's "Fünf Pittoresken, 3rd part: In futurum" is the first "silent" movement of a work written in the 20th Century, consisting only of a series of rests (it was preceded in 1897 by Alphonse Allais' silent "Funeral March for the Obsequies of a Great Deaf Man").
Schulhoff: "Sonata Erotica for female voice solo" (Dada-inspired, a soprano spends several minutes faking a carefully notated orgasm)
1920 Stravinsky's "Symphonies of Wind Instruments" further explores sudden changes in unrelated textures (jumps back and forth between multiple musical ideas)
Stravinky's "Pulcinella" premieres, signalling the "official" beginning of his Neoclassicism phase, a satirical/ironic yet affectionate return to old 18th Century music styles (opera buffa, etc...), sometimes using "wrong-note" tonality
Prokofiev's "Chout" (ballet) uses Neoclassical elements
In the 1920's de Falla develops a more spare style, inspired somewhat by Neoclassicism
Schoenberg: "Fünf Klavierstücke, Op. 23" (completed 1923), begins using 12-tone serialism in some parts.  These works however still use old forms (Baroque suite) to house the new methods of atonality.
Schulhoff's "Partita" begins to explore jazz melodies and rhythms in a classical setting (1st Movement: "all art is useless...")
Heitor Villa-Lobos' "Carnaval das Crianças" explores Brazilian carnival atmospheres
1921 Paul Hindemith: "Kammermusik No. 1", uses Neoclassicism's Baroque tonal (contrapuntal) forms (but bending the harmonies and adding tricky mechanical rhythms).  German Neoclassicism is less satirical, more respectful than French Neoclassicism, but more "pugnacious"
Webern: "Sechs Lieder Op. 14" ("Six Trakl Songs") (begun 1917), atonal works for voice, clarinets and strings
Luigi Russolo exhibits his noise machines ("Intonarumori") in Paris and is seen by Stravinsky, Honegger and Edgard Varèse.
Edgard Varèse: "Amériques" (1st version), influenced by Europe and Stravinsky (updated in 1928 to include the ondes Martenot).  
Ralph Vaughan Williams: "The Lark Ascending" (Neoclassic)
Schulhoff's "Suite for Chamber Orchestra" further develops his jazz tendencies
1922 Berg: "Wozzeck" (begun 1914)- atonal exploration of character, references tonality as well as classical forms in its movements
Stravinsky's "Mavra" satirizes opera buffa, using conventional rhythms and harmony
Varèse's "Hyperprism" uses exotic percussion
Ives: "114 Songs"
1923 Stravinsky's "Les Noces" (Russian choreographic scenes) uses Russian folk wedding music, but also the rhythmic cell technique.  An element of "ritualism" surfaces.
Stravinsky's "Octet for Wind"s and "Concerto for Piano and Winds" are inspired by Baroque structures and Bach, respectively, creating "brilliant and witty" string-less textures
Schoenberg: "Suite für Klavier", Op. 25 (begun 1921), the first work written completely in 12-tone technique.
Arthur Honegger: "Pacific 231", a driving orchestral work influenced by Futurism and trains.  Other "Futurist/Machine Age" composers include George Antheil, John Alden Carpenter ("Skyscrapers"), Prokofiev ("Le pas d'acier"), Alexander Mosolov (Op.19 "The Iron Foundry: Zavod/Machine Music") and Carlos Chavez ("Horsepower"). 
Darius Milhaud's "La Creation du Monde", a sleazy jazz ballet, is influenced by American Black music
Ravel's "Violin Sonata" (completed 1927) includes a "blues" movement
Henry Cowell: "Aeolian Harp", uses the inside strings of a piano. 
Alexander Tcherepnin: "Ajanta's Frescoes" ballet (inspired by ancient Indian cave paintings, draws connections between Eastern and Western music. 
Eugène Ysaÿe's "Six sonatas for solo violin" summarizes violin technique from Bach to the present time (whole tone and quarter tone scales, sul ponticello, Spanish folk elements, etc...) 
1924 Prokofiev's 2nd Symphony shows witty Neoclassic elements
Schoenberg's "Wind Quintet Op. 26" has serial elements, but uses 4 movements in traditional form (sonata, scherzo, etc…)
George Gershwin: "Rhapsody in Blue" approaches classical from the jazz side
Janáček: "The Cunning Little Vixen", opera, folk-like, uses ballet, mime, interludes, etc...
1925 Schoenberg: "Three Satires for Chorus" (criticizes Neoclassicism)
Harry Partch begins experimenting with alternate tunings
Varèse's "Intégrales" for wind and percussion (begun 1924) imitates backwards tape with acoustic instruments
Cowell: "The Banshee" for rubbed and scratched piano strings 
1926 Bartók: Piano Concerto 1 (influenced by folk scales, rhythms and harmonic forms).  Bartók begins using palindromic (mirror) and inverted forms, somewhat influenced by Neoclassicism (but without satire elements).
de Falla: "Harpsichord Concerto"
Jean Sibelius: "Tapiola" (works cease after this)
Berg: "Lyric Suite for string quartet" (begun 1925), serial and non-serial movements are based on a tonal background
George Antheil: "Ballet mecanique" premiered in Paris, which requires exotic percussion
Aaron Copland's "Piano Concerto" is influenced by jazz
Ernst Krenek's "Jonny spielt auf" opera includes jazz elements
Dmitri Shostakovich: Symphony No. 1
Bartok's "Out of Doors" piano work includes the movement "The Night's Music", which signals the beginning of his use of his "night music" texture, consisting of eerie chord clusters and/or ostinati with background melodies to evoke the natural sounds of night. 
Kodály: "Háry János" (Hungarian folk opera)
1927 Bartók: String Quartet 3
Stravinsky's "Oedipus Rex" (opera-oratorio ) is inpired by Baroque forms, but with additional modern day-influenced ritualistic elements
Schoenberg: 3rd String Quartet: begins loosening reliance on the old classical forms
Webern: String Trio
Varèse: "Arcana"
Tcherepnin: Symphony No. 1 (1st symphonic movement consists entirely of percussion).  Tcherepnin explores his synthetic "Tcherepnin scale" and his own contrapuntal "interpoint" technique. 
Hans Haass' "Capriccio fuge und intermezzo für mechanisches klavier" premieres at Donaueschingen and foreshadows Conlon Nancarrow's experiments with "supra-human" piano rolls  
1928 Bartók: String Quartet 4
Shostakovich's "The Nose" has Neoclassic satirical elements
Stravinsky's "Apollo" (for strings) inspired by French Baroque
Webern: Symphony Op.21 (12-tone using a 4-part canon, melodies are articulated by constantly-changing instrumental colors) - from here Webern's serial style crystallizes.  He never breaks the 12-tone rules or leaves serialism from here (he still draws from traditional forms though).
Schoenberg: "Orchestral Variations"
Berg's "Der Wein" for soprano and orchestra sets Baudelaire text with cabaret-tinged elements
Kurt Weill: "The Three-Penny Opera" has jazz and cabaret elements
Theremin and ondes Martenot invented
Ravel: "Boléro" uses hypnotic orchestration on repeating refrains
1929 Trautonium invented
Villa-Lobos: "Chôros" series completed (begun 1920) 
1930 Bartók: Piano Concerto 2 (completed 1931)
Poulenc:  "La voix humaine".  Poulenc's works also use Neoclassicism to satirize old forms or mix new and old genres to seductive or perturbing effect.  He sets Cocteau's words to music in an opera for solo soprano, "La voix humaine"
Amadeo Roldán: "Ritmicas"
Kurt Weill's "Rise and Fall of the City of Mahagonny" is a hit
Bartók: "Cantata Profana", which Bartók felt was his personal "credo"
Copland: "Piano Variations" (early atonal work)
1931 Stravinsky's "Violin Concerto in D" (Neoclassical style)
Varèse: "Ionisation", (one of) the first works for Western percussion orchestra.
Hindemith: Concertino for Trautonium and Strings (orchestra)
Carl Ruggles: "Sun-Treader" (begun 1926) uses "American-style" serial counterpoint (something like 8-tone pitch classes)
Ruth Crawford Seeger: "String Quartet" (quasi-serial but more rhythmic, 3rd movement begins exploring exploring a form of "total serialism" in that the rising/falling dynamics of held tones determine how collaborative melodies surface)
Ravel: "Piano Concerto in G" (jazz influenced)
1932 Schoenberg: "Moses und Aron": completes the 1st 2 acts, based on a single series
From Henry Cowell's design, Leon Theremin builds the "rhythmicon", a primitive drum machine/sequencer
Shostakovich: "The Lady Macbeth of the Mtensk District" (opera begun 1930)
1933 Partch: "The Seventeen Lyrics of Li Po", gains fame in New York doing solo shows
Ernst Krenek: "Karl V", opera, dabbles with serialism
Bartók: Hungarian Peasant Songs and Hungarian Folksongs arranged for orchestra (BB 107/108)
1934 Bartók: String Quartet 5
Webern: "Concerto for Nine Instruments" (uses Brandenberg-like form)
Messaien: "L'Ascension", uses Hindu rhythms for the first (but not last) time 
Varèse: "Ecuatorial", uses ondes Martenots or theremin-cellos
Kosaku (Kôsçak) Yamada: "Nagauta Symphony", incorporates Kabuki music elements and instruments
1935 Cowell's "Mosaic Quartet" features variable form structure (polyvalent)
Ives' "The Unanswered Question" (begun 1908, continued 1930) uses spatially separated groups with individual tempi.
Grainger's "free music" is performed for the first time to the public at one of his Melbourne broadcast lectures. 
Death of Alban Berg. 
1936 Bartók: "Music for Strings, Percussion and Celesta" (uses fugue elements, but not ironically as in Neoclassicism)
Prokofiev:"Romeo and Juliet", leaves Neoclassicism and returns to Romanticism 
Shostakovich's opera "The Lady Macbeth of the Mtensk District" is condemned and banned in Russia
Colin McPhee's "Tabuh-Tabuhan: Toccata for Orchestra" uses folk gamelan elements from Bali
Carl Orff: "Carmina Burana" (begun 1935)
Grainger: "Free Music No. 1" graphic notation for 4 theremins exploring non-scalar, non-metered melodies 
Varèse: "Density 21.5" for solo flute explores solo polyphony between atonality and modal scales
1937 Bartók: Sonata for Two Pianos and Percussion
Shostakovich: 5th Symphony (is forced to abandon wit and Neoclassicism and writes a more conservative work)
Berg: "Lulu", uses serial technique, but also "tonal schmalz" from saxophone and vibes
Messaien: "Fêtes des belles eaux for six ondes Martenots" 
1938 Stravinsky's "Dumbarton Oaks Concerto" (and later "Concerto in D" (1946)), also inspired by Bach's Brandenburg Concertos but less cynical than earlier Neoclassic works
John Cage begins writing "prepared piano" works.
Samuel Barber: "Adagio for Strings"
1939 Bartók: String Quartet 6
Webern's Cantata No. 1, related to Bachian cantata form
John Cage: "First Construction (in Metal)" based on rhythmic divisions of time.
John Cage: "Imaginary Landscape 1", first work using "live electronics" (test tone records).
Bartók: "Mikrokosmos" piano pieces (begun 1926).  Some pieces combine layers using different scales (Ex.: No. 148 has Phrygian over Ionian modes)
World War II begins.
1940 Stravinsky's "Symphony in C" uses tonal patterns and Neoclassic forms, no longer "corrupting" the old forms
Cage: "Bacchanale" for prepared piano
1941 Messaien's "Quatuor pour le fin de temps" is premiered in a prison camp.  This work also features an early use of bird song imitation.
Schoenberg: "Ode to Napoleon Buonaparte" for speech-song/sprechgesang vocal, piano and string quartet, mixes serial elements with tonal sections.  This vocal part also uses one of the earliest examples of graphic notation (indeterminate pitch).  His Piano Concerto (completed 1942) also has a more tonal approach to 12-tone composition.
Cage: "Third Construction" for 4 percussionists
1942 Copland: "Rodeo" ballet.  Copland begins exploring a form of "American Romanticism" (or Neoclassicism) which uses largely tonal American folk elements.  Many other American composers follow suit (William Schuman, Virgil Thomson, Walter Piston, Roy Harris, Ned Rorem, Leonard Bernstein, etc...).  Also "Fanfare for the Common Man"
1943 Bartók: "Concerto for Orchestra"
1944 Copland: "Appalachian Spring"
Benjamin Britten and Michael Tippett move from Neoclassicism to more conservative forms, inspired by English music of the past (Elizabethan madrigals, Purcell, etc…).  
Alan Hovhaness: "Lousadzak (The Coming of Light), Op. 48, concerto for piano & strings" (uses Armenian folk melodies with aleatoric notation)
Messaien: "Vingt regards sur l'enfant-Jésus" for piano.  Messaien explores what he calls "Modes of Limited Transposition".  
1945 Stravinsky's "Symphony in 3 Movements" uses tonal patterns and Neoclassic forms, originally written for war or religious filmscoring
World War II ends.
Bartók: 3rd Piano Concerto 
Deaths of Anton Webern and Béla Bartók.
1946 Schoenberg's String Trio uses serialism but recaptures some of the "craziness" of his earlier atonal works
Cage's "Sonatas and Interludes for Prepared Piano" begun (completed 1948)
Messaien's "Turangalîla-Symphonie" begun (completed 1948) uses exotic folk rhythms, as well as ondes Martenot
Britten: "Young Person's Guide to the Orchestra"
1947 Milton Babbit's "Three Composition for Piano" uses serialism applied to rhythm in a way different (more organic) than the Europeans in later years
Partch publishes "Genesis of a Music", describing his tuning theories. 
Pierre Boulez's 2nd Piano Sonata's level of difficulty makes him famous
In America, some composers explore ways of blending 12-tone technique with tonal harmony, but outside of American Romanticism/Neoclassicism (Stefan Wolpe (ex. "The Man From Midian", 1941), George Perle (ex. "Lyric Piece for cello and piano", 1946) and Leon Kirchner (ex. "Duo per violino e pianoforte", 1947), etc...) 
1948 Conlon Nancarrow: "Boogie-Woogie Suite" (begins using player pianos to realize his compositions)
Pierre Schaeffer:  "Étude aux chemins de fer", first piece of "musique concrète" (from tape-manipulated field recordings of trains).  This type of music would also later be described as "acousmatic" due to its enigmatic properties.  
Elliott Carter's "Sonata for Cello and Piano" breaks from (American) Neoclassicism and uses "metric modulation" (proportionate tempo changes) 
Cage: "Suite for Toy Piano, for toy piano or piano"
1949 Messaien: "Modes de valeurs et d'intensities" one of "Quatre études de rythme", which puts durations, dynamics and attack into ordered scales (modes), foreshadowing "total serialism" 
Messaien's "Turangalîla Symphony" premiered in Boston, conducted by Leonard Bernstein
1950 Pierre Schaeffer and Pierre Henry: "Symphonie pour un homme seul", a musique concrète radioplay 
Bebe and Louis Barron: "Heavenly Menagerie", the first electronic music work for magnetic tape, mostly by recorded circuits as they burned out (probably also the first examples of "circuit bending")
1951 Elliott Carter: 1st String Quartet, further explores metric modulation and atonal individuality, where the 4 string layers explore polyphonic tempi.
Stravinsky's "The Rake's Progress" uses Mozart's operas (Don Giovanni) as a foil
Cage's "Music of Changes" uses chance operations from the I Ching for compositional decisions
Cage's "Imaginary Landscape 4" uses radio signals as a sound source
Morton Feldman's "Projection" and "Intersection" works use aleatoric notation (1950-53) for quiet and held dynamics-based works (respectively)
Karlheinz Stockhausen: "Kreuzspiel", uses total serialism in a "jazz-tinged" way.
Boulez: "Structures" (completed 1952) for 2 pianos, uses total serialism, causes controversy and doubt on Boulez' part.  This is followeed by "Polyphonie X", which was subsequently withdrawn.
Boulez: "Etudes I sur un son" and "Etudes II sur sept sons" for electronic tape using total serialism (completed 1952) 
Cage: "Concerto for prepared piano"
Lou Harrison: "Suite for Violin, Piano, and Small Orchestra", explores Balinese gamelan timbres
Death of Arnold Schoenberg. 
1952 Cage: 4'33" (3rd silent piece after Allais and Schulhoff)
Earle Brown's "December 1952" (graphic score with free interpretation) 
Stravinsky's "Septet" confronts Schoenberg's serial music technique 
Cage: "Imaginary Landscape No. 5 for any 42 recordings" (free content collage)
Partch: "Castor and Pollux" for "Surrogate Kithara, Harmonic Canon, Diamond Marimba, Bass Marimba, and Cloud Chamber Bowls" 
Bruno Maderna: "Musica su due dimensioni" for flute and magnetic tape (1st use of tape with live instruments) 
Otto Luening and Vladimir Ussachevsky present the first "tape music" concert held in the United States (MoMA, NYC), featuring "Fantasy in Space" (flute recordings manipulated on magnetic tape) and "Sonic Contours" (overdubbed and processed piano layers) 
1953 Harry Partch creates his Gate 5 label/home in Sausalito, California
Earle Brown: "Twenty-Five Pages" for 1-25 pianos uses indeterminate form and graphic notation
Stockhausen: "Kontra-Punkte", groups serial points
Stockhausen: "Studie I", synthetic music from sine complexes, the first published score for electronic music
Cage: "Williams Mix" (begun 1952) 
Feldman: "Intersection for magnetic tape" (concrete sounds) 
György Ligeti: "Musica ricercata" for piano completed, using 1 additional pitch for each new section (begun 1951, foreshadowing the mechanistic "clocks" from his "clocks and clouds" style)
Messaien: "Réveil des oiseaux" for piano and orchestra  This work is entirely from bird songs, and compresses a 12-hour field transcription into 20 minutes, at the same time slowing down the individual birdcalls. 
Henry Brant: "Rural Antiphonies", explores spatial orchestration
Wolpe: "Enactments, for 3 pianos" (begun 1950, independent layers of chromaticism and, "organic modes" influenced by Arabic maqams) 
Moondog's album "Moondog on the Streets of New York" (among others) is released.  Moondog's work, influenced by street sounds of New York City and featuring some invented instruments, would influence the early Minimalist composers. 
Alberto Ginastera: "Variaciones concertantes" (explores "subjective nationalism", or Argentinian folk culture) 
1954 Iannis Xenakis: "Metastasis" (uses statistical sound mass and glissandi)
Boulez: "Le Marteau sans Maitre" is completed (begun 1952) utilizes exotic sounds and rhythms from Bali and Black Africa to add variety to serialism
Varèse "Déserts" for wind, percussion and tape (begun 1949), alternates tape with orchestra.  The premiere in Paris is introduced by Boulez, and Stockhausen does the sound mix.
Ligeti: String Quartet No. 1: "Métamorphoses nocturnes" (1st mature work but still inspired by Bartok and using chromatic motifs in traditional form, begun 1953)
1955 Jean Barraque: "Séquence" (serial, but influenced by Romanticism, begun in 1950)
Partch: "The Bewitched (A Dance Satire)" 
Astor Piazzolla: "Sinfonía de tango" (creates "nuevo tango", a modern blend of tango with modern music) 
Hovhaness: Symphony No. 2 ("Mysterious Mountain") (anticipates the "Holy Minimalism" movement?) 
Stockhausen: Zeitmasse, uses player ability as a tempo scale value (layers of tempos)
1956 Messaien: "Catalog d'oiseaux" for piano (more bird song transcriptions, completed 1958)
Stockhausen's "Gesang der Junglinge" uses concrete recordings of a boy soloist with synthetic tones and spatializes them
Xenakis: "Pithoprakta" based on statistics
Ussachevsky: "Piece for tape recorder"  
1957 Stockhausen's "Gruppen" treats large instrumental groups in different tempo proportions (and spacial placement).  Each group is composed with layers based on scales of rhythmic subdivision in order to imitate harmonic overtone properties.
Stockhausen: "Klavierstuck XI", uses indeterminate form
Boulez: Third Piano Sonata, uses indeterminate form 
Lejaren Hiller: "Illiac Suite for String Quartet", composed by a computer
Berio:"Allelujah II" (begun 1955) for 5 orchestra groups
Toru Takemitsu: "Requiem" for string orchestra (impresses Stravinsky)
Varèse: "Poème électronique" (begun 1956), collage piece for the 1958 Brussels Exhibition
Henri Pousseur:"Scambi (Exchanges)" electronic work open to multiple form realizations 
1958 Boulez: "Poesie pour pouvoir" for spatialized tape and orchestra 
Berio: "Sequenza I" for flute (contains first notated multiphonic, Berio would continue with a series of pieces for different instruments exploring solo extended technique and often theatricality)
Cage: "Aria" for voice (as 10 "characters")
Cage: "Variations I" uses transparencies to create aleatorically-created scores
Cage: "Fontana Mix" for tape, based on transparencies
Cage: "Concert for piano and orchestra" (using many aleatoric notation techniques)
Ligeti: "Artikulation" electronic music (begins developing the concept of "micropolyphony" from working at the WDR Electronic Music Studio)
Xenakis: "Diamorphoses" and "Concret PH", Xenakis' first electro-acoustic works
Mauricio Kagel's "Anagrama" (begun 1957) for vocalists and chamber orchestra presents an excerpt of Dante's "Divine Comedy" in 4 languages
La Monte Young: "Trio for Strings" (serial work based on extremely long drones and silences) 
1959 Stravinsky's "Movements for piano and orchestra" is influenced by Stockhausen's music (?), and begins to approach serialism
Stockhausen: "Zyklus", explores indeterminate form and scales of indeterminacy
Giacinto Scelsi's  "Quattro pezzi su una nota sola" approaches his mature style of monotonal harmony
Roberto Gerhard: "Audiomobiles I-IV" (begun 1958, electronic music at the BBC Radiophonic Workshop)
Daphne Oram invents "Oramics", in which sound is synthesized by "drawing" on film (prior to this she and Desmond Briscoe founded the BBC Radiophonic Workshop in 1958).
Xenakis: "Duel" for 2 small orchestras, explores "game theory"
Carter's 2nd String Quartet further explores independent tempo schemes
Galina Ustvolskaya: "Grand Duet For Violoncello And Piano" (Ustvolskaya's works explore a uniquely powerful and stark austerity in her approach to spiritual/sacred themes)
Berio: "Différences" (for flute, clarinet, viola, cello, harp and tape, where the tape is processed sounds of the pre-recorded acoustic quintet)
1960 Messaien's "Chronochromie", last major birdsong work, uses an 18-layer birdsong polyphony in Epode
Stockhausen: "Carré" for 4 choir and 4 orchestra groups uses "moment form"
Stockhausen's "Kontakte" for tape with/without piano and percussion applies serial technique to electronic music
Berio's "Circles" for voice, harp and percussion, written for vocalist Cathy Berberian explores voice and theatricality
Cage: "Cartridge Music", for amplified sounds (1st "live electronic music")
Kagel: "Sur Scene" (includes a musicologist's lecture and performers practicing scales, warming up, etc...as part of the work)
La Monte Young: "Compositions 1960", a series of Fluxus-inspired works 
Krzysztof Penderecki: "Threnody to the Victims of Hiroshima" uses graphic notation with massed string clusters   
1961 Ligeti's "Atmosphères" rejects the serial method and instead explores "micropolyphony" (vibrating, melodically indistinct sound masses, the "clouds" from his "clocks and clouds" style).  Repurposed in Stanley Kubrick's film "2001: A Space Odyssey"
Boulez: "Structures II" for 2 pianos (a "looser" version of "Structures I")
Nancarrow "Studies for Player Piano: Study No. 21" layers 2 voices with changing tempi.   
Ginastera: 1st Piano Concerto (4th mvmt later arranged for rock band by ELP) 
Penderecki: "Polymorphia" (some pitch shapes based on encephalogram readings taken on people listening to "Threnody to the Victims of Hiroshima")
Berio: "Visage" for voice and tape (with Cathy Berberian) 
James Tenney's "Collage #1 (Blue Suede)" samples and recycles Elvis Presley 
Mel Powell: "Electronic Setting" (Benny Goodman's swing pianist turns to serial and electronic music, also "Events for Tape Recorder (1963)) 
Luigi Nono's "Intolleranza 1960" (a protest opera)
1962 Messaien's "Sept haïkaï" is inspired by Indian tâlas and Japanese Gagaku music (4th mvmt), as well as birdsong
Stockhausen: "Momente" (completed 1969) using moment form.
Cage: "Atlas Eclipticalis" for an ensemble of 86 instruments (begun 1961)
Ligeti: "Poème Symphonique, for 100 metronomes" (inspired by Fluxus movement)
Ligeti: "Aventures" for voice (uses polyphonic nonsense words, also modified for use in Kubrick's "2001".  This would be further explored in "Nouvelles Aventures" (1962–65))
LaMonte Young creates his own performing group, The Theatre of Eternal Music, which included members John Cale and Terry Riley and played music based on proportionate drone frequencies.. 
Britten: "War Requiem" for chorus and orchestras
Peter Maxwell Davies: "Taverner" (1962-1970) opera, reworks pre-Baroque forms (plainchant, etc...) with avant-garde techniques 
Mario Davidovsky: "Synchronisms No. 1 for Flute and electronic sound" (first of a series of electro-acoustic works) 
1963 Ligeti: "Requiem" for chorus, soloists and orchestra (completed 1965, also used in Kubrick's "2001")
Luc Ferrari: "Hétérozygote" (collage tape)
Lukas Foss: "Echoi" (mixes improvisation with atonal scoring)
1964 Babbitt: "Ensembles for Synthesizer" (total serial electronic music, begun 1962) and "Philomel" (voice and synthesizer/processed vocal tape)
Terry Riley: "In C" uses tonal, aleatoric modal fragments in C
Xenakis: "Eonta" for piano and brass quintet, uses a computer to calculate stochastic (statistical) values
Stockhausen: "Mixtur" (uses ring modulation on orchestra groups)
Stockhausen: "Mikrophonie I" (uses close-miked noises from a manipulated giant tam-tam)
Ben Johnston: String Quartet 2 (microtonal, 53 notes to an octave) 
Nono's "La Fabbrica illuminata" blends soprano with tape recordings of factory workers and factory environments in order to make a connection with the "common people".  He would later incorporate recordings of street protests and speeches by Fidel Castro.
La Monte Young: "The Well-Tuned Piano" (begun, uncompleted), an improvisatory work for specially-tuned piano. 

Harrison Birtwistle: "Tragoedia" for flute, oboe, clarinet, bassoon, horn, harp and string quartet
Cage: "Rozart Mix" for tape loops
Steve Reich: "It's Gonna Rain" (tape loop experiment using the idea of rhythmic phasing) 
Bernd Alois Zimmerman: "Die Soldaten", opera, employs "klangkomposition pluralism", which includes speech-song, large orchestra, electronics, and Bach quotes, influenced by Berg's "Wozzeck". 
Hovhaness: "Fantasy on Japanese Woodprints" for Xylophone and Orchestra (inspired by Japanese culture)
Death of Edgard Varèse. 
1966 Stockhausen: "Telemusik", appropriates folk music recordings for electronic manipulation (ring modulation and filtering)
Ligeti: "Lux Aeterna" for chorus (also used in Kubrick's "2001")
Penderecki: "De natura sonoris No. 1" for orchestra 
Kirchner: String Quartet 3 for strings and tape (Pulitzer Prize winner) 
Partch: "And On The Seventh Day Petals Fell In Petaluma" (begun 1966, one minute verses of duets, trios, quartets, quintets, and one septet, essentually a showcase/pedagogical work for Partch's invented instruments) 
Zimmermann: "Musique pour les soupers du roi Ubu" (instrumental collage of other popular classical works) 
John Eaton: "Concert Piece for Syn-Ket and Orchestra" (uses an early micro-tonal Moog-related synthesizer)
Hovhaness: "Vishnu Symphony (No. 19)" (aleatoric modal elements to create statistical structures) 
Kagel: "Musik für Renaissance-Instrumente", "Kammermusik fur Renaissance-Instrumente"
1967 Stockhausen's "Prozession" uses process symbols (plus-minus symbols) to direct aleatoric performer actions
Stockhausen: "Hymnen" (national anthems as musique concrete with electronics)
Cornelius Cardew: "Treatise" (begun 1963), consisting of 193 pages of graphic notation open to free interpretation.  The previous year saw Cardew join AMM, a free improvisation group. 
Babbitt: "Correspondences" for synthesized tape music and string orchestra 
Morton Subotnick: "Silver Apples of the Moon" (uses electronic synthesis technology developed by Don Buchla) 
Ligeti: "Lontano" for orchestra
Toru Takemitsu's "November Steps" for shakuhachi, biwa, and orchestra contrasts Japanese traditional and Western classical music 
1968 Stockhausen's "Kurzwellen" uses shortwave radio with live electronics
Stockhausen's "Stimmung" uses aleatoric overtone singing
Stockhausen: "Aus Den Sieben Tagen" (intuitive music (improvisation) based only on text)
Musica Elettronica Viva (MEV): "Sound Pool" and "Free Soup", with members including Alvin Curran, Richard Teitelbaum, Frederic Rzewski, and Allan Bryant, invites open, public improvisations in its performances
Alfred Schnittke: 2nd Violin Sonata (begun 1967), explores "polystylism" 
Ligeti: "Ramifications" for "mistuned" string orchestra (quarter-tones) and String Quartet 2 (indeterminate microtonality smaller than quarter tones)
Helmut Lachenmann's "temA" for chamber group concentrates on "breath noises", and marks the beginning of his "mature period" where he explores the concepts of "touch".
Witold Lutosławski: "Livre pour orchestre" (4 orchestral 'chapters' separated by aleatoric interludes) 
Annea Lockwood: "Piano Transplants" (1968-1982, including "Piano Burning", 1968) in which the performer plays freely as a piano is slowly destroyed (by fire or exposure to natural elements)
Jacob Druckman: "Animus II for mezzo-soprano, percussion and electronic tape", begun 1967 
1969 Berio: "Sinfonia" (begun 1968, middle movement quotes many works, all contained in a scherzo from Mahler's "Resurrection Symphony")
John Cage and Lejaren Hiller: "HPSCHD" for 1 to 7 amplified harpsichords playing permutations of Mozart, Beethoven, Chopin, Schumann, Gottschalk, Busoni, Schoenberg, Cage and Hiller) and 1 to 51 tapes of computer music (begun 1967), the LP includes a score for manipulation of the stereo controls when listening to the record
Nancarrow: "Studies for Player Piano: Study No. 37" (1965-69) has 12 somewhat canonic voices in 12 independent tempi schemes.
George Crumb's "Night of the Four Moons" for voice and a few exotic instruments (slide banjo, Kabuki blocks, etc...) is inspired in part by Mahler’s "Das Lied von der Erde" and Haydn’s Symphony No. 45 ("Farewell"). 
Carter: "Concerto for Orchestra"
Per Nørgård: "Voyage into the Golden Screen" (explores his "Infinity Series") 
Cardew forms the Scratch Orchestra, which melds improvisation with simple music structures in an attempt to create a "communal situation"
Horatiu Rădulescu: "Credo" for 9 cellos (1st "spectral music" work, which orchestrates 45 layers of harmonics of a C fundamental) 
Merrill Leroy Ellis: "Kaleidoscope, for Orchestra, Synthesizer, and Soprano" (collaboration with Robert Moog)
Philip Glass: "Music in Similar Motion" (explores repetitive phrases at different levels of unison and syncopation) 
Charles Wuorinen "Time's Encomium" for electronic tape (begun 1968, Pulitzer Prize winner) 
1970 Reich: "Phase Patterns" and "Four Organs" (along with Riley's 1964 "In C") helps usher in Minimalism with the use of "phasing"
Stockhausen: "Mantra" (begins a new phase of "formula compositions" based on articulated melodies) 
Mauricio Kagel: "Acustica" for experimental sound-producers and loud-speakers (begun 1968)
Ligeti: "Continuum" for harpsichord begins exploring rhythmic complexity
Lachenmann's "Pression" (for cello) and "Guero" (for piano body) explores new timbres from bowing pressure and other extended techniques ("musique concrète instrumentale")
Brian Ferneyhough's "Cassandra's Dream Song" for flute explores difficult notation (aleatory elements come from the "impossible"  technical demands, "not literally realisable"), signalling the beginning of the "New Complexity" movement.  Other New Complexity composers eventually include Michael Finnissy, James Dillon, Chris Dench and Richard Barrett (FURT).
Davidovsky: "Synchronisms No. 6 for Piano and electronics" (Pulitzer Prize winner) 
Iancu Dumitrescu: "Sound Sculptor (I), spectral music for piano" 
Crumb: "Black Angels" for electric string quartet, percussion, crystal glasses, tam-tams, etc…
Crumb: "Ancient Voices of Children" (creates eerie vocal effects from singing into an amplified piano)
Hovhaness: "And God Created Great Whales" (taped whale songs and orchestra) 
Luc Ferrari's "Presque rien No. 1: Le Lever du jour au bord de la mer" explores organized field recordings as music 
1971 Reich: "Drumming" (phasing with beat substitution, includes bongos, marimbas, glockenspiel and voice)
Glass: "Music in 12 Parts" (completed 1974)
Shostakovich's Symphony No.15 quotes Rossini's "William Tell" and Wagner
Feldman: "Rothko Chapel" 
Christian Wolff: "Burdocks" (begun 1970) for one or more groups of five or more players uses indeterminate form based on layering of 10 entirely different types of composition (including the word "flying" as one of them) 
Kagel: "Exotica" for 6 singing instruments with 10 or more non-European instruments  (aleatory elements come from the players' ignorance of their instruments' playing techniques)
Gavin Bryars: "Jesus' Blood Never Failed Me Yet" (field recording of a homeless person's chant is looped and orchestral elements are added on top)  
Druckman: "Synapse" (electronic tape, to be played leading into his contrabass solo "Valentine (1969)) 
Elliott Carter's 3rd String Quartet has 2 duos play separate and independently
Lou Harrison "La Koro-Sutra" (uses his own homemade "American gamelan" percussion kit)
Death of Stravinsky. 
1972 Schnittke's Symphony No. 1 further explores "polystylism" (begun 1969), which includes quotations from Bach, Haydn, Beethoven, Chopin, Strauss, etc... as well as "jazz improvisation episodes".
Dieter Schnebel begins writing his "ReVisionen" (completed 1989?) which are reworkings of classic works by Bach, Beethoven ("Beethoven-Sinfonie"), Wagner ("Wagner-Idyll"), Webern ("Webern Variationen"), Verdi ("Verdi-Moment"), Mozart, etc...
Henryk Górecki: Symphony No. 2, Op. 31, "Copernican" (violent, contrasting sound masses leading to hymnal textures)
Lachenmann's "Gran Torso" for string quartet further explores new string timbres from string pressure
1973 Boulez: "...explosante-fixe", begins to explore live sound manipulation
Brian Ferneyhough's "Unity Capsule" for flute (completed 1976) 
Ustvolskaya: "Composition No. 2, Dies Irae, for eight double basses, piano and wooden cube" (uses a large beaten wooden cube of her own design)
1974 Gérard Grisey: "Périodes" for septet (Grisey would help popularize "spectral music" by exploring tone color derived from analyzing overtone structures.  This work would become part of the larger work "Les espaces acoustiques", completed 1985)
Rădulescu: "A Doini" for bowed vertical concert grand pianos, spectrally retuned 
Stockhausen's "Inori" uses a melodic formula and dancer-mimes which interpret the music in gesture-based scales
Wolfgang Rihm's "Morphonie-Sektor IV" at the Donaueschinger Festival marks the beginning of a return to more "conservative" musical styles (eventually leading to the "New Simplicity" movement). 
Wojciech Kilar: "Krzesany" (influenced by songs and dances of the Tatra Mountains in southern Poland, ending includes a loud free improvisation crescendo) 
1975 Stockhausen: "Sirius" (uses the EMS Synthi 100 synthesizer to compress and expand melodies both horizontally and vertically)
Cage: "Etudes Australes", for piano (begun 1974)
Cage: "Child of Tree", for amplified cactus (or amplified plant materials)
Frederic Rzewski's "The People United Will Never Be Defeated" applies 19th and 20th century piano vocabulary to a Chilean protest song in a set of 36 variations
Bernard Parmegiani: "De Natura Sonorum" (musique concrete) 
Salvatore Sciarrino explores fleeting harmonics and similar extended textures with "Sei Capricci" for solo violin (completed 1976)
1976 Glass: "Einstein on the Beach" (opera)
Arvo Pärt: "Für Alina" (begins using his "tintinnabuli style", where notes of a scale melody are combines with notes of a resonating triad)
Louis Andriessen's "Hoketus" uses chromatic cells in a minimalistic way 
Maurice Ohana's "Sacral d'Ilx" uses harpsichord, brass and wind and multiphonics to evoke "ancient" traditions 
Carter: "Symphony of Three Orchestras" (4 groups with overlapping movements and 12 types of music)
1977 Stockhausen: "Der Jahreslauf" (contemporary classical scored for traditional Japanese Gagaku orchestra) 
Stockhausen begins working on his "LICHT" opera cycle, which would incorporate all of his future works for almost the next 29 years
Xenakis: "Jonchaies" for 109 musicians (Xenakis explores tribal rhythm in his own personal style and incorporates some Balinese melodic elements)
Lachenmann's "Salut für Caudwell" for 2 acoustic guitars explores slides, muffled picking and harmonics over and around the soundhole  
Ligeti: "Le Grand Macabre" ("anti-anti-opera") 1st ver completed (begun 1975)
Górecki: Symphony No. 3, Op. 36 ("Symphony of Sorrowful Songs", begun 1976) (using medieval modes, not popularized until 1992, with Pärt, first of the "Holy Minimalists") 
Pärt: "Tabula Rasa" for two violins, prepared piano, and chamber orchestra 
Silvestrov's "Quiet Songs"/"Silent Songs", settings of classic Russian poems for voice and piano using Romantic style give the feeling of "perpetually ending" 
1978 Pärt: "Spiegel im Spiegel"
Grisey: "Jour, Contre-jour" (completed 1979) for electric organ and ensemble, explore spectral drone music 
1979 George Crumb: "Makrokosmos" 4 volumes for amplified piano (begun 1972)
Xenakis finishes the computer program UPIC, which can convert images to music (such as "Mycenae Alpha" from the previous year)
A movement dubbed "New Simplicity" arises (including Rihm) which rebels against the complexity of avant garde music and turns back towards traditional harmony, melody and forms
Oliver Knussen: Third Symphony (begun 1973, engages both early 20th century expressiveness and Carter-like rhythmic complexity) 
Grisey: "Tempus ex Machina" (later expanded into "Le Noir de l'etoile" (1989-90), explores polyrhythmic pulse rates) 
Brant: "Orbits, a Spatial Symphonic Ritual for 80 Trombones, Organ and Sopranino Voice"
Sciarrino: "Un'immagine Di Arpocrate"
1980 Boulez' "Répons" (revised 1984) uses computer transformation on percussionists with orchestra, premiered at IRCAM.
Tristan Murail: "Gondwana" (orchestral spectral work based on harmonics from bell and trombone sounds)
Claude Vivier: "Lonely Child" (spectral music with more melodic and ritual elements)
Morton Subotnick: "After the Butterfly" (trumpet and chamber instruments with "ghost electronics") 
John Stump: "Faerie's Aire and Death Waltz (from 'A Tribute to Zdenko G. Fibich')" :)
1981 Stockhausen's 1st opera, "Donnerstag aus LICHT"/"Thursday from Light" is premiered.
Sciarrino's "Efebo con Radio" (for voice and orchestra) imitates the sound of scanning through popular radio stations (including static)
Arthur Kreiger: "Variations On A Theme By Davidovsky" (first (?) electronic work based on variations of a previous electronic work)
1982 Stockhausen's "Lucifer's Farewell" has a male chorus enact a drama in a church and then release a live bird at the end
Rădulescu: "Clepsydra" for 16 "sound icons" (side-turned open string pianos)
Tenney: "Clang" (spectral work for aleatory chamber orchestra)
Lou Harrison: "Double Concerto (begun 1981) for violin, cello, and Javanese gamelan
1983 Feldman: 2nd String Quartet, (up to) 6-hours long, explores large scale but quiet surfaces
Cage: "Ryoanji", using graphic notation to determine pitch, based on the Japanese sand garden
John Adams: "Shaker Loops" (explores (mostly) tonal and minimalistic tremolo, trill and ostinati patterns) 
Murail: "Désintégrations" (for tape and 17 players, begun 1982)  
Frank Denyer's "After the Rain" explores non-Western instrumentation and pulsing, natural processes 
1984 Ferneyhough: "Etudes Transcendentales" for voice and 4 instruments
Stockhausen's 2nd opera, "Samstag aus LICHT"/"Saturday from Light" is premiered.
John Zorn's "Cobra" combines his previous "game piece" explorations in free improvisation group dynamics (begun in the late 1970's with "Lacrosse", "Hockey", "Pool", "Archery", etc...) and gives the performers advanced abilities to form and direct subgroups of improvising ensembles within the larger ensemble.  His next work, "Xu Feng" would begin to add musical directives to the free improvisation structures (dynamics, tempo, styles, etc...).
Rădulescu: "Das Andere" explores solo string harmonics in just intonation
Grisey: "Les Chants de l'amour" (begun 1982, for 12 voices and tape) 
Tenney: "Spectral CANON for CONLON Nancarrow" (begun 1982, for player piano, 24 harmonics pulsing at their frequency ratios) 
Sciarrino's "Hermes" explores flute harmonics in wide dynamic ranges (as well as other extended techniques)
1985 Ligeti: "Études pour piano", Book 1, six etudes exploring polyrhythms, partly inspired by music from sub-Saharan Africa
Luigi Nono: "Prometeo" (begun 1981) opera with multiple orchestras and live sound manipulation 
1986 György Kurtág: "Kafka-Fragmente" (begun 1985) for soprano and violin: 40 short movements inspired by the stark miniatures of Webern (chromatic but not 12-tone).  Kurtág addresses the music of the past with the extreme sonorities of the present.
Stockhausen: "Xi", explores microtonal scale timbres for wind soloist
Birtwistle: "Earth Dances, for orchestra"
Grisey: "Talea" (begins applying spectral music techniques to faster structures) 
Sofia Gubaidulina: "Stimmen Verstummen" (symphony in 12 movements, features a silent "conductor's solo").  Gubaidulina uses exotic and unusual instrumental groupings in her work in a kind of spiritual chromaticism. 
1987 Adams: "Nixon in China"
Philip Glass: Violin Concerto No. 1
Tod Machover: "VALIS", an electronic opera using "hyperinstruments" (motion-controlled effects) based on Philip K. Dick's book. 
Rădulescu: Streichquartett Nr. 4, Opus 33: "Infinite to be cannot be infinite, infinite anti-be could be infinite" (begin 1976, 9 string quartets, making 128 + 4 strings, create a spectral "viola de gamba") 
Zorn: "Spillane" (uses "file-card" system to organize "sound scenes" based on a literary theme, uses studio overdubbing and jazz improvisation elements) 
Cage begins writing his "Number Pieces" which use indeterminate time notation ("time brackets")
1988 Ligeti: "Piano Concerto" (begun 1985)
Stockhausen's 3rd opera, "Montag aus LICHT"/"Monday from Light" is premiered.
Nono: "La lontananza nostalgica utopica futura" (completed 1989, violin solo with 8 tapes of pre-recorded and processed violin, adjusted by the sound mixer) 

-----

Links
Modern Music A Concise History (Paul Griffiths)
Modern Music and After, 3rd Edition (Paul Griffiths)
Summary of Western Classical Music History (Marlon Feld)
Music, Instruments and Innovations During the 20th Century (Espie Estrella)
Music history online : Music of the 20th century (Brian Blood)
Music since 1960 (The Rambler blog, Tim Rutherford-Johnson)
A guide to contemporary classical music (Tom Service, The Guardian)
A Brief History of Developments in 20th Century Classical Music, related to the compositional style of Frank Zappa (Chris Sansom)
20th Century Style
MICROCOSMS: A Simplified Approach to Musical Styles of the Twentieth Century (Phillip Magnuson)