Twenty years after its release, Phish’s double-CD collection A Live One has something rare and precious going for it: it still doesn’t sound like anybody else. Oversized, perverse, requiring an unusual amount of listener background knowledge? Yes to all. Yet the collective improvisations it captures, unprecedentedly coherent yet freewheeling and open-ended, are unique in rock ‘n’ roll.This book considers the music and moment of Phish’s ecstatically inventive 1995 live document, a mix of weirdo acid-psych, ambient moonscapes, vaudevillian Americana, and riotous arena-rock energy, all filtered through bandleader Trey Anastasio’s screwball compositional sensibility and the band’s idiosyncratic approach to spontaneous group creativity. It places Phish and their fandom in historical and cultural context, and picks apart the mechanics of their extended group jams. And it examines the mystery of how a quartet of nice boys from Burlington, VT could have been, all at once, one of America’s biggest touring acts and one of its best-kept secrets.