When the Clash was labeled “The Only Band That Matters,” it may have been record company hype, but when I was a teenager, there was probably no band that mattered more to me. The idealism, the earnest anger, the democratic, sometimes clumsy way of mixing styles and sounds — I am almost as susceptible to it now as I was at 15. This is all by way of disclosure: It’s likely that I would have been stirred and moved by “Joe Strummer: The Future Is Unwritten,” even if it were the straightforward, VH1-ready rock star biography it might, at first, appear to be. The film, however, is much more than a biography of the Clash’s guitarist and lead singer: It’s history, criticism, philosophy and politics, played fast and loud. Directed by Julien Temple, an able and tireless chronicler of the pop life, “Joe Strummer” assembles clips and interviews into a fast-moving timeline. Mr. Strummer’s voice, captured from radio broadcasts and old conversations, provides narration and companionship. That his presence is limited to audio and archival material provides a sad and subtle reminder of his absence, of the void left by his sudden death at 50, from a heart attack, in 2002. Like Mr. Temple’s two movies about the Sex Pistols — the eyewitness “Great Rock ’n’ Roll Swindle” (1980) and the revisionist “Filth and the Fury” (2000) — “Joe Strummer” is not so much a portrait as a collage. Sometimes the images are conventionally documentary, serving as literal illustrations of the story. But just as often they provide a kind of free-associative context, reminding us that an individual’s life is made up not only of experiences and events but also of ideas, dreams and possibilities. So while we are treated to marvelous and rare footage of the Clash in rehearsal and Mr. Strummer’s previous bands in performance, we also sample news video and snippets of the cartoon version of “Animal Farm. ”