frank zappa was the father of invention, the most caustic iconoclast of the rock-and-roll era. ''my job,'' he once said, ''is extrapolating everything to its most absurd extreme.'' and zappa, who died of prostate cancer saturday on december 4, 1993 at age 52, clearly loved his job.

blessed with an agile mind that embraced astoundingly diverse styles of music and rejected moral and intellectual hypocrisy, zappa made non-conformity his credo. experimentalism was his methodology, satire and social commentary his weapons and the american way of life his target. in this bull's-eye, church and state were united and ideological lines dissolved. he was an all-purpose gadfly and maverick, the i.f. stone of rock, though he sometimes came across as its alfred e. neuman with long, stringy black hair and the omnipresent mustache and goatee.

zappa, of course, was worried: about artistic integrity, about musical adventurousness, about free speech. his 1979 epic, ''joe's garage,'' dealt with what would happen if music were illegal; this was six years before the parents music resource center recommended voluntary album labeling and zappa went to capitol hill. there, he accused a senate committee of fostering censorship and branded the pmrc ''a group of bored washington housewives'' who wanted to ''housebreak all composers and performers because of the lyrics of a few.'' he later memorialized the encounter in ''frank zappa meets the mothers of prevention,'' which included the 12-minute ''porn wars'' using sound bites from the hearing.

zappa's distrust of authority was cemented in 1962-long before he rose to fame with the mothers of invention. then a budding movie maker and recording studio owner, he was set up by the san bernardino vice squad, one of whose undercover agents commissioned an audio-only sex tape, which zappa and his girlfriend made as a joke (they edited out the laughs). however, they were convicted of ''conspiracy to commit pornography'' and zappa spent 10 days in jail and three years on probation (the conviction did spare him the draft).

born in baltimore on dec. 21, 1940, frank zappa came to california at age 10. his father was a meteorologist who researched poisonous gases for the military (gas masks hung on the wall of the family home in case of accidents). he started his musical career as a high school drummer in garage bands like the black-outs and the school marching band (he was thrown out after the bandmaster caught him smoking in uniform).

zappa always said his life, and musical tastes, changed in 1954, when he read a look magazine story on the sam goody record chain, which cited its ability to sell such ''weird'' music as ''the complete works of edgar varese, vol. one.'' when zappa finally found a copy, he embraced its avant-garde dissonance, though his parents would let him play it only in his room. it was there, then, that the musical mix began, for zappa was just as deeply into howlin' wolf and the orioles.

zappa once said he felt ''stuck between the slide rule and the gutbucket'' and much of his career could be seen as an attempt to reconcile those two extremes. he recalled first composing as a high school sophomore and writing classical music at 18-he didn't write rock-and-roll until his early twenties. his penchant for composing, as opposed to performing, was first evident in soundtracks concocted for the b-films ''run home slow'' (written by his high school english teacher) and ''the world's greatest sinner'' (for which he put together a 52-piece orchestra).

but zappa also liked having an audience, and in rock he found not only that, but an environment in which he could explore new sonorities. his restless invention was evident in an unproduced early '60s pop opera titled ''i was a teenage maltshop'' (narrated by high school buddy don van vliet, soon to become captain beefheart) and such bands as the muthers, soul giants and captain glasspack and his magic mufflers, the latter renamed the mothers on mother's day, 1964. the ''of invention'' was added later by nervous mgm records executives, who thought the name otherwise too salacious.

even in the mid-'60s, the mothers of invention were a band apart, out of the underground yet still of it by dint of their at times unmanageable iconoclasm. as the sleeve of their 1966 debut album, ''freak out,'' noted of zappa: ''sometimes he sings. sometimes he talks to the audience. sometimes there is trouble.'' the first double album debut, ''freak out,'' included one whole side, ''return of the son of the monster magnet,'' that was a homage to edgar varese.

the mothers followed that album with ''absolutely free'' (whose ''plastic people'' became an anthem of the czech underground) and ''we're only in it for the money,'' which viciously lampooned the hippie/alternative culture that was the band's principal audience. their principal target, of course, was middle america, castigated on songs like ''brown shoes don't make it'' and ''who are the brain police?'' in a six-month residency at new york's garrick theater, the mothers created a visceral style of improv that was half comedy, half music. much of the music from this time featured a wild juxtapositioning of styles providing a cushion for zappa's mordant wit.

but zappa, the mothers' chief writer, arranger, conceptualist and leader, was growing increasingly frustrated. it showed up in 1968's ''cruisin' with ruben and the jets,'' in which the mothers assumed an early rock alter ego celebrating what zappa called ''cretin simplicity.'' but mothers records didn't sell well and live work was erratic. the avant rock maestro became increasingly unhappy with the financial losses, the musicians themselves (''music comes from composers, not musicians,'' he wrote in his autobiography) and the mothers' audiences: ''i got tired of playing for people who clap for all the wrong reasons.'' he disbanded the mothers in 1970-for a while, anyway-touring under his own name and the burden of his rock history.

though zappa hated ''fetishists'' who believed the only good music he ever made was with the original mothers, he was at least partially to blame. while there had always been much caustic wit in his lyrics, 1970's ''road ladies'' began a string of stupid, lascivious songs that would lead many folks to dismiss his body of work. among them: ''dinah-moe humm'' (about a woman who said she couldn't have an orgasm), ''illinois enema bandit'' (based on a true story) and 1974's ''don't eat the yellow snow.''

the last turned out to be zappa's first hit single (after a deejay cut it from 10 minutes to three and played it as what it was-a novelty). zappa's few other hits were equally absurd: 1979's ''dancin' fool'' satirized disco, and 1982's ''valley girl'' satirized california's shopping mall culture. it featured his then 14-year-old daughter, moon unit. the other children were named dweezil, ahmet rodan and diva. typically, frank zappa insisted his kids would always have more trouble because of their last name.

his own name came to stand for restless invention and reinvention. zappa was a pioneer in digital recording technology and a textbook study in the search for artistic independence.

the labels brought a measure of independence and provided a home to such acts as alice cooper, captain beefheart, gtos, tim buckley, the persuasions and lord buckley, as well as for zappa, who gradually reacquired the rights to all of his music.

and there was a lot of it, from the earliest glimmer of jazz-rock fusion on 1968's ''king kong'' to 1984's ''thing-fish,'' a decidedly odd musical comedy that came with its own libretto. sometimes underestimated as a guitarist -- he once titled a series of solo guitar albums ''shut up 'n play yer guitar'' -- zappa in recent years focused on the synclavier synthesizer. he spent much of the last eight years supervising the reissue of old albums and such ambitious collections as ''you can't do that onstage anymore,'' six double cds of previously unreleased live recordings. and he was embraced as a serious composer in at least some quarters. he recorded several albums with pierre boulez and the london symphony orchestra and last year was honored, along with karlheinz stockhausen and john cage, at the 1992 new music festival in frankfurt. ''the yellow shark,'' an album of ensemble modern's performances of his music at that festival, was released a few weeks ago.

but though he recorded more than 50 albums -- most are still available -- and retained a hard-core following in the states, zappa was better appreciated overseas. zappa albums were smuggled into czechoslovakia before the fall of communism and vaclav havel, the playwright-turned-president, was so moved that he made zappa a special ambassador to the west for culture. but the appointment was derailed by pressure from the state department, then run by james baker -- whose wife, susan, was a co-founder of the pmrc.

if zappa was perceived by foreigners as a seminal figure in rock history, the verdict here seemed to be that he was a peripheral one. for instance, even after his illness was disclosed three years ago, zappa was twice rejected for induction by the rock and roll hall of fame. perhaps the voters remembered zappa's curt dismissal of rock journalism as ''people who can't write interviewing people who can't talk for people who can't read.''

frank zappa could be contemptuous, but that savage wit also served him well in a business where integrity and honor are rare.