(The following is an excerpt from my book on avantgarde music and the composers are not rated).

Avantgarde music blossomed during the 1960s, although it was still viewed as a fringe phenomenon by the establishment of classical music.

The freewheeling spirit of the 1960s took advantage of the technical innovations of the years after World War II. The three revolutionary schools of the time had changed the rules: Cologne (Stockhausen) had introduced purely electronic music; New York (Cage) had introduced music of gestures not only sounds; Paris (Schaeffer) had introduced music of non-musical sounds. The 1960s basically gave those novelties an ideological substratum, closely related to the counterculture and hippie movements of the time.

Morton Subotnick, Terry Riley, Pauline Oliveros and others founded the "Tape Music Center" near San Francisco in 1959. In 1961 Robert Ashley and Gordon Mumma organized Ann Arbor's ONCE festival, entirely devoted to avantgarde music. The Fluxus movement first realized the interdisciplinary implications of John Cage's ideas. A group of musicians, painters and writers, formed in New York by Lithuanian-born artist George Maciunas in 1961, they organized chance events bordering on theater, visual art and music. Their works of art were sets of rules that specified the process by which the performers had to produce the music and the audience had to consume it. These happenings demystified the apparatus of western classical music while reintroducing a ritualistic element.

The first technical director of the Tape Music Center, Michael Callahan, was still a teenager when he helped poet Gerd Stern create the multimedia show "Verbal American Landscape". The duo then moved to New York where in 1964 they helped Steve Durkee form USCO, whose first mentor was a luminary like Marshall McLuhan at the University of Rochester. Their multimedia performance "Who R U" shocked San Francisco in 1964. In 1966 their show "Shrine" at New York's Riverside Museum coined the term "be-in".

Together, these events marked the end of avantgarde music as an exclusive of seasoned (and mostly European) composers and the beginning of avantgarde music as a relatively grass-roots (and mostly American) phenomenon.

It was a time when new ideas proliferated rapidly. While some of them would remain obscure for decades, eventually several of them would start brand new genres of music and even tricke down into popular music. While in Paris during the 1950s, Brion Gysin invented of the "cut-up" technique (made popular in literature by his friend William Burroughs), producing the first audio collages. Hans Otte was the first visionary of "deep listening" music, composing brief piano sonatas in which very little happens, inspired by Eastern philosophy. In 1963, Czech artist Milan Knizak began to create music (the so-called "Destroyed Music" series) out of scratched, warped, defective and damaged records. The idea of playing "glitches" was going to remain confined to the realm of pure folly until the end of the century. The postmodernist aesthetic fostered the use of "quotation" from the past in the composition of new works, for example George Rochberg's Contra Mortem Et Tempus (1965), Bernd Zimmermann's Die Soldaten (1964), Luciano Berio's Sinfonia (1968), Peter Maxwell Davies' St Thomas Wake (1969), George Crumb's Ancient Voices of Children (1970). Amplifying one of Cage's intuitions, some ventured into "event music", music whose score depends on the gestures/movements/actions of the performers, and sometimes "is" those actions, for example: Dieter Schnebel's third movement of Abfaelle (1962) for conductor alone (with no musicians), Franco Donatoni's intricate chance strategies of Zrcadlo (1963), Lukas Foss' improvised Echoi (1963).

Minimalism, the style that stormed the USA during the mid 1960s, was an odd compromise between classical and avantgarde music, and an odd compromise between high-brow and popular music. Based on the repetition of minimal tonal units, it was a music with no narrative/emotional development, but it was mostly tonal. It overcame the inherent limitation of the repetition by letting gradual variations alter the composition slowly over time. By their nature, minimalist compositions emphasized trance instead of reasoning, and therefore matched the zeitgeist of the hippie era. On the other hand, they emanated spirituality instead of irreverence, and therefore lacked the provocative edge of, say, Cage's music. La Monte Young, a Fluxus member, composed his first music for sustained tones in 1957. The term "minimalism" originally referred to his "dream house", a New York loft in which Young and his Theater Of Eternal Music (comprising violinist Tony Conrad, viola player John Cale, trumpet player Jon Hassell, keyboardist Terry Riley and others) developed a music made of semi-stationary waves, of slowly evolving amorphous sound. Music became a living organism. Colossal pieces such as The Tortoise His Dreams And Journeys (1964) and The Well Tuned Piano (1964) offered little or no respite for western harmony, and created a bold bridge between John Cage's "alea", Buddhist meditation and psychedelia. The former was the prototype for a special case of minimalism: droning minimalism, relying on extended (and apparently eternal) tones.

One of his disciples, Terry Riley, became the guru of minimalist repetition with the pulse-based ensemble work In C (1965), that centered on the iteration of simple patterns (almost a human-based imitation of tape loops), and explored the raga-psychedelic connection with the solo electronic improvisation Rainbow in Curved Air (1968), that employed tape loop delays. These works clearly introduced repetition as a main compositional technique in western music, with (Rainbow In Curved Air) or without (In C) melody. This conceptual revolution mirrored the sociopolitical revolution of the time, when communal and improvised concerts prevailed over the formal presentation of classical music. Riley was emblematic of a generation of musicians who were looking for a new tonal vocabulary to express a sense of wonder.

The master of "slow motion music" was Steve Reich, who gradually came to employ chamber ensembles and small orchestras for his masterpieces Drumming (1971), Music For 18 Musicians (1976), Music for a Large Ensemble (1978).

Philip Glass began from similar premises with the arduous repetitive patterns of Music In Twelve Parts (1974) but later rediscovered melody and approached the format of the opera from a different perspective with Einstein On The Beach (1976).

A less prominent (at the time) but no less influential group of musicians was devoted to "droning" minimalism.

LaMonte Young's associate Tony Conrad composed long tone pieces in just intonation for bowed strings such as Four Violins (1964).

Alvin Lucier returned to LaMonte Young's stationary waves but from a mathematical, scientific point of view in works such as Music For Solo Performer (1965), that used the performer's brainwaves, I Am Sitting In A Room (1970), that progressively degraded speech while progressively amplifying the background noise of the environment, Still And Moving Lines Of Silence (1974), an eight-part work for classical instruments and electronic devices, Music On A Long Thin Wire (1977), that used the vibrations of a metallic wire.

Phill Niblock tried to create music without rhythm or melody by slow accumulation of microtones. Niblock's droning soundscapes originated from the superimposition and juxtaposition of sustained sounds which were, in turn, obtained from reprocessing acoustic instruments.

Accordionist Pauline Oliveros, the most significant purveyor of "deep listening" music, explored the psychological effects of sound in works such as Horse Sings From Cloud (1975), a sequence of "om" for voice and accordion, Wanderer (1982), a polyrhythmic symphony for an ensemble of accordionists and percussionists, and the spiritual solo improvisation of Roots Of The Moment (1988). Her work Deep Listening (1988) for voice, accordion, trombone, didjeridu and found sounds, recorded in an underground cistern, gave the school its name. Primordial Lift (1998) was a mini-symphony for droning instruments.

These works virtually invented a new form of chamber music.

Yet another current was preoccupied with the way that electronics could be used to produce maximum emotional impact.

Gordon Mumma crafted the dense and apocalyptic sonic masses of his electro-acoustic sculptures Megaton (1963), a mixture of improvised action-music and tape collage, the pioneering multimedia show Space Theatre (1964), and another angst-ridden experiment with collage and electronics, Dresden Interleaf (1965).

The chaotic tornadoes of Morton Subotnick, such as Silver Apples Of The Moon (1967), The Wild Bull (1967) and Touch (1968), took Edgar Varese's "electronic poem" to another dimension, a dimension that blurred the distance between primitivism and futurism, between tribal and binary percussion, between ancestral sound and alien noise. Their dense textures and hectic counterpoint, approaching the intensity and cacophony of rock'n'roll, completely redesigned the landscape of western music.

Tod Dockstader, a self-taught sound engineer and sound-effect specialist who scored soundtracks for Hollywood cartoons, influenced by both Pierre Schaeffer and Edgar Varese, produced tapes such as Eight Electronic Pieces (1960), Apocalypse (1966) and especially Quatermass (1966), visionary works with a narrative and dramatic emphasis.

AMM was one of the early ensembles of live electronic music, first documented in the free improvised pieces of AMMusic (jun 1966 - ? 1967), featuring Cornelius Cardew on piano and cello, Lou Gare on tenor saxophone and violin, Eddie Prevost on percussion, Keith Rowe on guitar, Lawrence Sheaff on cello, accordion and clarinet (and three of them also on transistor radio).

Another ensemble of live electronic music, Musica Elettronica Viva, formed by Frederic Rzewski, Alvin Curran and Richard Teitelbaum, recorded Rzewski's monumental Spacecraft (1967).

The recordings by Jon Appleton, such as Syntonic Menagerie (? 1966/? 1969 - ? 1969) and Human Music (feb 1970 - ? 1970), with jazz trumpet player Don Cherry, introduced electronic instruments to a wider audience.

Ralph Lundsten was one of the first European composers to experiment with the new medium, as documented on Elektronmusikstudion Dokumentation 1 (jun 1965/apr 1966 - ? 1966).

Igor Wakhevitch, a student of Pierre Schaeffer, blended electronic music, psychedelic rock and classical opera on his intimidating albums Logos (? 1970 - ? 1970), Docteur Faust (? 1971 - ? 1971) and Hathor (sep 1973 - dec 1973).

Ilhan Mimaroglu, a student of Vladimir Ussachevsky and Edgar Varese, gave electronic music a political agenda with La Ruche (1968) for electronics, cello, harpsichord and piano, and the 35-minute electronic collage Tract (1972), a "composition of agitprop music for electromagnetic tape".

One important strand in the evolution of the avantgarde was the exploration of the human voice as an emotional medium and musical instrument. In 1970 Gloria Coates began experimenting with vocal extensions and creating multiphonics.

Meredith Monk coined a vocabulary of vocal sounds that she used to create theatrical performances. The Key (1970), Education Of The Girlchild (1973), Tablet (1977), Turtle Dreams (1983), Dolmen Music (1979), Atlas (1991) focus on acrobatic and schizophrenic mutations that run the gamut from child to witch. They populate the music of characters, moods and states of mind.

Yoko Ono, a student of John Cage, practiced a mixture of dissonant western music, Japanese kabuki recitation and visceral screeching that projected her stream of consciousness, a technique documented on the album Yoko Ono/ Plastic Ono Band (feb 1968/oct 1970 - dec 1970).

Finally there was computer music, possibly the least publicized at the time.

James Tenney was probably the first composer to craft an aesthetic for computer music. Tenney realized that electronic and digital music almost forced the composer to accept noise as "music" and to abandon the idea of absolute control over a composition. While employing and developing compositional algorithms (initially Max Mathews's "digital synthesis" software), he thus came to accept John Cage's passion for indeterminacy. Furthermore, the composer of computer music could better achieve her or his artistic vision by focusing on "stochastic" quantities, the elements that define the overall structure (the "gestalt"), rather than trying to specify each single element of each single second of music. Thus the Dialogue (1963) between pure noise and pure tones, and the abstract dissonant soundscape of Phases (1963).

Charles Dodge used a computer in Earth's Magnetic Field (1970) to translate astrophysical data into electronic sounds.