“Eat That Question: Frank Zappa In His Own Words” pulls together interview, concert and behind-the-scenes footage to commemorate one of the rock era’s most idiosyncratic star musicians. Thorsten Schutte’s entirely archival assemblage is most likely to be appreciated by the previously converted, as its stimulating if somewhat patchy overview of a multi-various career skims over or omits too many aspects to comprise a definitive introduction. Sony Classics picked up worldwide rights (excluding France and Germany) at Sundance.

A self-taught composer and multi-instrumentalist primarily interested in avant-garde music, the young Zappa is seen wresting sounds from an adapted bicycle (accompanied by studio band) on the syndicated “Steve Allen Show” in 1963. Also heavily influenced by free jazz, such experimentation won much attention if not wide commercial success with 1966’s “Freak Out,” his first album with the Mothers of Invention.

It established him as a challenging outlier in the rock field, one adored by the adventurous few but fundamentally at odds with a music industry he soon came to loathe. It also introduced his penchant for biting social satire, not just via ever-quotable lyrics but parodies of popular music idioms. He branched out into filmmaking with the video-shot 1971 cult feature “200 Motels,” and further honed his knowledge of diverse new technologies producing his own records and other artists’. The greater embrace of his more “difficult” music abroad was reflected in the European outlets granted his classical compositions in later years before he died of prostate cancer in 1993, at age 52.

Perhaps understandably declining to convey the musical breadth of a career that encompassed more than 60 albums (and that’s not counting nearly as many posthumous releases), “Eat That Question” places its primary emphasis on Zappa as a public personality, a podium he seemed wary toward yet seldom shrank from. Seen interviewed over the decades in different countries, he often appears bored, caustic and condescending in response to admittedly often trite questions. But he’s always sharply articulate in airing firm opinion on nearly any given subject.

He was particularly outspoken in opposition to Tipper Gore’s Parents Music Resource Center (PMRC), which pressed the music industry to put warning labels on records with content deemed unfit for impressionable young minds. While Zappa’s own frequent resistance to “good taste” in song themes and use of profanity cast him as a rebellious figure, it’s worth noting that his skepticism toward organized politics encompassed the left as well as the right. And despite his own long-running “hippie freak,” he had little patience for the rampant drug use of the rock world.

One curious running thread is the frequent description of Zappa (even by himself) as “ugly,” which judgment seems based primarily on his having a prominent “Jewish nose.” Curious because, apart from that matter-of-personal-taste feature and his years of somewhat unruly big hair, he was quite conventionally handsome.

The mix of diverse talking heads as well as performance and miscellaneous footage here is always entertaining. But in sticking to archival materials and (almost exclusively) Zappa’s own voice, it leaves numerous key life details out. They include a 1965 vice-squad arrest for allegedly producing pornographic materials that no doubt helped shape his fiercely anti-censorship stance; the output of his several self-owned record labels, which advanced such envelope-pushing artists as Alice Cooper, Wild Man Fischer and Lenny Bruce; his court battles (mostly to own complete rights to his work); the long-term impact of a serious onstage accident in 1971; later filmic endeavors like 1979’s “Baby Snakes” and 1987’s “Uncle Meat;” and his rare, satirical pop semi-hits (notably “Valley Girl,” just mentioned in passing here). Presumably those missing chapters will be covered in a forthcoming Zappa documentary by Alex Winter, which (like “Eat That Question”) has the full cooperation of the Zappa Family Trust.

While the archival materials (much shot in now-archaic video formats) are variable in quality, assembly is first-rate.