FRANK ZAPPA is one of the most unclassifiable figures in American popular music. A passionate devotee of rhythm and blues, he fused rock with jazz and atonal music. His persona was half angry Beat hipster and half loopy Mad magazine satirist. Barry Miles’s new biography, ”Zappa,” argues that he was a major artist in the line of Courbet and Duchamp. Despite sometimes tendentious overstatements, the book does indeed establish that Zappa, through his genre-shattering experiments, technical virtuosity and staggering productivity, deserves to be considered a central figure of late-20th-century American culture.