Every person’s life if full of little moments that become seminal only in retrospect. We simply aren’t wired to process the significance of a moment as it happens. Often, we go to our deaths only vaguely aware of the moments and people who shaped our identities, leaving it to acquaintances we left behind to define us.

In Julian Temple’s documentary, The Future Is Unwritten, it’s largely left to the acquaintances and notable fans of Joe Strummer to define him. Strummer, lead singer, rhythm guitarist and unofficial head honcho of the Clash, had already left this mortal coil, having died in his sleep 21 December 2002. Even at that, his presence is felt throughout the film, as he largely narrates the history of his too-short life. Far from being a gimmick, his narration—culled from his 1990’s BBC radio program and various interviews through the years—adds an extra dimension to his turbulent and enigmatic life.

Fittingly, the narrative approach of The Future Is Unwritten is in itself enigmatic and non-linear. Utilizing family home movies (dating from Strummer’s early childhood, when he was just wee John Mellor), archival footage from the times that shaped his life, animation based on his cartoon drawings, and live Clash footage, Temple’s film comes across as more a rich collage than a biography. The end result is a portrait of a Joe Strummer who was not merely the “punk rock warlord” he fancied himself to be. That was only one facet of Strummer’s personality, the one he most often let his public see. He was a lot more complicated than that.

Temple, whose previous films include the Sex Pistols documentary The Great Rock ‘n’ Roll Swindle, paints Strummer as a conflicted soul here. He was ruthless in his pursuit of being a rock star, tossing his mates the 101ers to the curb when he was given the opportunity to join the upstart band the Clash. Once he went punk, he played the role to the hilt, and infused it with a political agenda not seen before in the idiom. That’s not to take anything away from Clash mates Mick Jones or Paul Simonon—they were the musical backbone of the band—but it was Strummer who guided the band into a new phase of rock music. And for a time they lived up to their self-proclaimed hype of being the only band that mattered.