For a man who was so mercurial creatively, Frank Zappa was resolutely focused and consistent throughout his career when it came to his message about who he was and what he did: he was a musician, and he just wanted to be free to make the music he wanted to make for the fans who wanted to hear it. He was a family man and a working artist, not a druggie or a cult leader or a symbol.

That essential humility is the core takeaway from Thorsten Schütte's Eat That Question, a new documentary that tells Zappa's story in his own words, through first-person TV interviews he conducted throughout his long and winding career. Whatever you think of Zappa's music, you'll leave the theater with a deeper appreciation of who this prodigiously gifted musician was and what he meant to popular culture.

I haven't listened to a lot of Zappa; few have, though virtually everyone's heard of him. Almost everyone has an idea of who Zappa was and what his music was about, but only a small slice of the population have invested the time to really understand his musical legacy. Throughout Eat That Question, Zappa seems both wary and weary, continually expecting — usually correctly — that he was being interviewed by someone who knew his music was "obscene" or "outrageous," but didn't know why or how.

Born in 1940 in Baltimore, Zappa — yes, that was his real name — had a deep musical curiosity and enormous talent, and his central locus of fascination was the nexus of avant-garde rock and classical music. As Woody Guthrie was to Bob Dylan, iconoclastic composer Edgard Varèse was to Zappa: an aesthetic and philosophical beacon. In the earliest clip shown in Eat That Question, Zappa appears on The Steve Allen Show in 1963 to play a semi-improvised concerto for bicycle. The host was invited to play along, but that didn't mean that Zappa saw the performance as a joke: the idea that serious music could be funny was a theme that would run throughout Zappa's career.

By the time the Mothers of Invention released their debut album in 1966, Zappa had already found success as a film composer and notoriety as a convicted pornographer (he and a woman faked the sounds of sex for a tape to be played at a stag party). Freak Out! made Zappa a "rock star," a label he'd retain for the rest of his career even though it only scratched the surface of his many interests and accomplishments. Live footage in Eat That Question shows Zappa's gonzo magnetism as frontman of the Mothers, who I gather you really had to see live to truly appreciate — with their symphonic satire, they sounded something like what you might get if David Letterman fronted Pink Floyd.

By the '80s, Zappa found himself squarely in the center of the Culture Wars; his interviews of the era spark with an indignant passion as he excoriates censors ranging from religious fundamentalists to "common sense" moms like Tipper Gore, whose Parents Music Resource Center advocated for the application of explicit-content labels. Even those labels, thought Zappa, were the first step on a slippery slope that led to the debasement of art and the abridgment of personal freedoms.

Having been disinvited from the Royal Albert Hall in the '70s due to the explicit content of his show 200 Motels (a show posthumously realized, gloriously, by the Los Angeles Philharmonic at Disney Hall), by the final decade of his life Zappa was well-known and widely (though not universally) respected in the classical music world. A priceless interview in Eat That Question has Zappa explaining that he was presenting an orchestral concert of his work at the Barbican because...well, just because he could.

That was how he lived his life, and Eat That Question presents Zappa as a tireless defender of an artist's right to free self-expression. He knew his work was aesthetically challenging, and he very deliberately made it socially and politically challenging. He had an audience that reliably supported him, and he knew that most people outside that audience really had very little understanding of what his work was about.

In these interviews, Zappa often appears sardonic and detached, even pained. Watching 90 minutes of that sounds torturous, but it's redeemed by Zappa's sincere self-effacement and by his unfailing articulateness. Eat That Question is easy to recommend for anyone who wants to better understand this essential figure of 20th century music.