Few figures of the American avant-garde wore as many hats as Earle Brown. Composer, graphic notation pioneer, member of the New York School alongside John Cage, Morton Feldman, and Christian Wolff - but also, and crucially, a record producer whose ear shaped one of the most important document series in 20th century music. Between 1960 and 1973, working first for Time Records and then Mainstream Records, Brown curated the Contemporary Sound Series - 18 LPs presenting works by 49 composers from 16 countries. It was nothing less than a panoramic survey of the international avant-garde as it was happening, captured by someone who understood its language from the inside.

The original pressings, discontinued in 1978, have long been among the most coveted artifacts in the world of experimental music on vinyl. Wergo's meticulous reissue programme, undertaken in collaboration with the Earle Brown Music Foundation, digitally remastered by Udo Wüstendörfer and packaged in six 3CD box sets, finally makes these historic recordings accessible again. Vol. 1 alone spans a remarkable arc - from the rhythmic experiments of the American percussionist-composers of the 1930s and '40s to the radical electronic improvisations of the late 1960s.

The first disc, Concert Percussion for Orchestra, originally issued in 1961, gathers works by Amadeo Roldán, Lou Harrison, William Russell, Henry Cowell, and Cage - performed by the Manhattan Percussion Ensemble under the direction of Cage and Paul Price. These are foundational pieces: Cowell's Ostinato Pianissimo, Cage and Harrison's Double Music, Cage's Amores - works that redefined the role of percussion in Western concert music, opening it to the polyrhythmic structures of Cuba, the timbral subtleties of prepared piano, the democratic possibilities of noise. The second disc pairs Karlheinz Stockhausen's Zyklus and Refrain with Mauricio Kagel's Transición II, performed by Christoph Caskel, David Tudor, and Aloys and Bernhard Kontarsky - towering performances of the European post-serial avant-garde at the height of its ambition.

The third disc is perhaps the most radical of all: Live Electronic Music Improvised, the legendary split LP originally released on Mainstream in 1968, featuring Musica Elettronica Viva from Rome - Allan Bryant, Alvin Curran, Frederic Rzewski, Richard Teitelbaum, and Ivan Vandor - and AMM from London - Cornelius Cardew, Lou Gare, Christopher Hobbs, Eddie Prévost, and Keith Rowe. MEV's Spacecraft and AMM's contribution, drawn from the now-legendary Crypt sessions, represent two parallel but distinct visions of collective electronic improvisation - one rooted in the communal spirit of 1960s Rome, the other in the radical abstraction of the British experimental tradition. Two of the most important ensembles of the 20th century, captured at the very moment they were redefining what music could be.

Packaged in a box with three CDs in jewel cases and four booklets containing liner notes by Alfred Frankenstein, Stockhausen, Kagel, Cardew, and Rzewski, in English, German, and French.