Walter Zimmermann's Desert Plants: Conversations with 23 American Musicians, published 1976, long time out of print, is now accessible again on Walter's website, here.
If you who don't know Desert Plants, you should. It's a landmark both for American experimental music and for its account of a young West German composer discovering his own musical sensibility, grounded in a relationship to history and geography, through an encounter with a musical "other", in this case a collection of American musicians who, at the time, received almost as little attention at home as they did abroad. While several of the musicians interviewed remain less well-known or well-known only in niches, with the passage of time the music of many of those included in Desert Plants has attained a prominence that sometimes makes it hard to recall how great a challenge their music posed to the then-establishment (and, to some extent, still-institutional) avant-gardes, American and European alike.
(For the record, my opinion here is completely biased. I was fortunate to find a copy of Desert Plants around '78 or '79 while still in High School and many of the interviews — and the music those interviews drove me to — registered like lightning, a real source of inspiration, no, better: posture, funky typos and all, alongside Cage's writings, Lou Harrison's Music Primer, Nyman's Experimental Music and Peter Garland's magazine Soundings. When, with my wife, I moved to Frankfurt a decade later — knowing vaguely that Frankfurt was a town in which new music was taken seriously (you know: Adorno, for better or worse and all that) — I had no idea where the Walter Zimmermann of Desert Plants might be living, but I called the only Walter Zimmermann in the Frankfurt phone book and it turned out to be the right one. Since then, Walter has become a mentor and friend, an encouraging and nurturing presence, and his music, alongside his sensitivity, ethical stance, musical/cultural/culinary appetite and fine sense of adventure as well as moral support, has been a constant gift.)