The composing, conducting apostle of the new music (""Schoenberg is dead!"") would boggle a conventional biographer with his all-work/no-life regimen, but Peyser is content to wrap her chronicle of the musical avant garde's last thirty years around a profile in the New Yorker manner. Morsels of life style and a handful of tight-lipped quotes from the subject and his sister (""Women are not important to him"") have to make do in the personal department. But the byzantine network of composer rivalries, betrayed loyalties, stolen thunder, and dogmatic choosing-upsides more than compensates for the dearth of Boulezian romance, with Stravinsky, Cage, and Stockhausen, among others, filling the vacant roles of father, brother, and son. Unfortunately, the intricacies of these scenarios can't quite be appreciated without ingestion of strong doses of theory and analysis. Serial? Aleatory? Music of chance? Peyser handles technical discussion as humanely as anyone; nonetheless, laymen will occasionally be stymied. But they should return for the book's final movement: Boulez's just-completed, controversial occupancy of the New York Philharmonic podium. Here the paradoxes explode--the elitist longing for full houses, the ascetic reveling in hero-worship, the fanatical anti-traditionalist conducting Mendelssohn. Peyser's round-the-clock surveillance of the maestro during the New York years pays off, as do her canny marshaling of extracts from Boulez writings, and even her Freudian could-be's. Half hatchet-job and half canonization, Boulez is dense, thorny, required reading for aficionados--and off-limits for almost everybody else.