The Duke of Prunes FRANK ZAPPA 1940-1993 OBITUARY BY MICHAEL WALSH FROM TIME MAGAZINE Frank Zappa surely would have appreciated -- indeed, relished -- the irony that his death last week was, as the old show-biz line has it, a shrewd career move. The musical iconoclast, best known for his work with the seminal 1960s rock band the Mothers of Invention, was in many ways the prisoner of his own raffish image: hirsute hippie freak; countercultural sire of prototypical Valley Girl Moon Unit Zappa and her siblings Dweezil, Ahmet and Diva; opinionated crank (''AIDS is a CIA plot''); and First Amendment scourge of Tipper Gore. With his death from prostate cancer, a few days short of his 53rd birthday, it may now be easier to appreciate an often overlooked fact about Francis Vincent Zappa: he was the most protean and adventurous American composer of his generation. Yes, composer. ''The only reason I went into rock 'n' roll,'' he explained, ''is because I couldn't get anybody to play the classical music that I wrote.'' During a career that spanned three decades, Zappa never pretended or wanted to be anything else. On the first Mothers' album, 1966's Freak Out!, he quoted the maxim of his hero, the '20s avant-gardist Edgard Varese: ''The present-day composer refuses to die.'' They were words he lived by. In addition to his 12 albums with the Mothers and his numerous other rock recordings, Zappa collaborated with the likes of composer Pierre Boulez and conductor Zubin Mehta on such pieces as The Perfect Stranger, a collection of chamber music, and 200 Motels, an ''opera for television.'' The self-taught Zappa was as prickly and puckish about his ''serious'' music as he was about rock. ''I write,'' he declared, ''because I am personally amused by what I do, and if other people are amused by it, then it's fine. If they're not, then that's also fine.'' Born in Baltimore, Zappa was the son of a Sicilian-born meteorologist and metallurgist who worked for a poison-gas manufacturer -- the inspiration, perhaps, for his later Prelude to the Afternoon of a Sexually Aroused Gas Mask. The family moved to California when he was 10, and young Frank grew up in Lancaster, north of Los Angeles. ''I developed an affinity to creeps,'' he recalled, ''and I've surrounded myself with them ever since.'' At 15 he read a magazine article that referred to Varese's audacious compositions as ''the ugliest music in the world,'' and he knew he had to hear them; for a birthday present, he cajoled his parents into letting him telephone the old man, then 72 and living in New York City. Throughout his life, Zappa's music was both eclectic and uneven. At his worst he could be amateurish, as in the early Return of the Son of Monster Magnet. On guitar Zappa was no Eric Clapton, and as a band the Mothers were no match for Lou Reed's raw Velvet Underground, with whom they shared an in-your-face aesthetic that guaranteed zero radio play. At his best, however, Zappa fused two seemingly irreconcilable 20th century musical strains; his masterpiece, Absolutely Free (1967), is a dazzling merger of Stravinsky and Varese with rock and rhythm and blues. Who else would have thought to counterpoint the Berceuse from Stravinsky's Firebird with the doo-wop of Duke of Earl on a song called The Duke of Prunes? To quote The Rite of Spring and Petrouchka as a prelude to some of the hardest-charging, straight-ahead rock of the era? To use Varese's musique concrete, which alters conventionally produced sounds to create an electronic effect, in a paean to rock-groupie archetype Suzy Creamcheese? His post-Mothers work, including Lumpy Gravy (1967), which Zappa called a ''curiously inconsistent piece which started out to be a ballet but probably didn't make it,'' never quite reached the same freewheeling, free-associating level, although it became more ambitious and technically accomplished. In such works as The Yellow Shark, a 90-minute program of his instrumental music performed last year in Europe, his natural predilections for spiky, dissonant sonorities and unusual sound effects were fully in evidence, exemplifying his Cage-like motto of AAAFNRAA -- ''Anything anytime anyplace for no reason at all.'' By the end of his life, Zappa had all but abandoned rock; the '60s icon who had posed sitting naked on a toilet for a poster called Phi Zappa Krappa was instead encouraging young audiences to register to vote and battling censorship of rock lyrics. After cancer was diagnosed in 1990, he worked 14 hours a day in his home studio in the Hollywood Hills, composing a musical called Thing-Fish and contemplating an opera. With Suzy Creamcheese finally grown up, Zappa dropped the entertainer's mask, revealing the face of the artist beneath. ''My music,'' he said, ''makes the mind think.'' Copyright 1993 Time Inc. All rights reserved.