Hollywood ? Julien Temple was hanging around Clash shows in 1976, filming the band’s explosive emergence on a borrowed 16 mm camera, when he dropped them as a subject in favor of the Sex Pistols and “The Great Rock ‘n’ Roll Swindle.” More than 30 years later, the footage would find its way into “Joe Strummer: The Future Is Unwritten,” a tribute to The Clash’s frontman and lyricist, Joe Strummer, who died suddenly of heart failure in 2002 at age 50.

A beautiful, evocative collage composed of concert footage, photographs, interviews and film clips, as well as interviews with people who knew him, the film is a rigorously thorough biography and an impassioned accolade. Temple spends as much time on Strummer’s life before and after The Clash as he does charting the band’s powerful musical and political influence.

The son of a diplomat, Strummer (John Graham Mellor) was born in Ankara, Turkey, and spent the first years of his life in Cairo, Egypt, and Mexico City before being sent to boarding school. After dropping out of art school and going to live in a squat, he began busking on the subway and formed a band to help raise money for fellow squatters. After being introduced to Mick Jones and Paul Simonon by legendary punk manager Bernie Rhodes, however, Strummer abruptly dropped his old hippie ways (and friends), and became the frontman for the act that eventually would be known as “the only band that matters.”

The Clash’s rise was meteoric, and its time together fulminating and relatively brief. Idealistic, iconoclastic and politically engaged, Strummer struggled with the idea that they had become the kind of band they had set out to destroy – the kind of band, like The Rolling Stones, for instance, who “drove limousines into swimming pools.”

By the end of 1983, Jones and drummer Topper Headon had been fired from the band, and The Clash would dissolve three years later. But Strummer’s commitment to his ideals would only become more apparent and mature over time, as would the devotion of his fans. “The Future Is Unwritten” includes broadcasts from Strummer’s radio show, “London Calling,” which lasted from 1998 to 2002, and which boasted, to his surprise, 40 million listeners worldwide.

Footage and clips of Strummer and the band are interspersed with “campfire” scenes, inspired by Strummer’s legendary campfires, begun at the Glastonbury Festival. The idea of the campfire, a communal place for people to share stories and discuss ideas, was central to Strummer’s ethos, representing a coming together of all types of people. (Later in life, he would regret having turned on his old friends, saying, “We’re all hippies.”) Family, friends, bandmates, former friends, former bandmates and a smattering of celebrities sit in front of campfires and talk about his life and legacy.

Temple’s somewhat fluid, stream-of-consciousness approach and his aversion to subject-identifying titles make it clear that “The Future Is Unwritten” isn’t meant to be an introduction to a legend quite as much as it’s intended to be a gift to devoted fans.