Legend: "Marley"

What were Bob Marley's favourite kind of doughnuts? I ask, because it's one of the very few questions left unanswered by Marley, Kevin Macdonald's comprehensive and very reverent two-and-a-half documentary account of how a young boy born into poverty in a shack in St. Ann's, Jamaica, came - over the course of three decades - to become one of the world's most legendary recording acts. Macdonald's approach is straight-ahead and mostly chronological, though there remain surprises tucked away in its sidebars: who knew the music industry at one point attempted to rechristen the reggae star as Adam, or that he was first discovered while working alongside Desmond Dekker in what must surely have been the world's most tuneful welders' workshop?

Marley's success is couched as a Freudian triumph over the absent English father who turned his back on his son at a crucial moment, inspiring the song "Cornerstone" ("The stone that the builder refused/Will always be the head cornerstone", which suggests an ignorance of the construction industry's methods). Yet this is also a journey tangled up with issues pertaining to Marley's mixed heritage: as Macdonald sees it, the boy who was ostracised at school for being neither one thing nor the other ended up negotiating his own path between black and white cultures. The Wailers, Marley's longtime musical cohorts, bore the influence of such white-friendly crossover acts as The Temptations and The Platters, and had their first Jamaican hit with a cover of Dion and the Belmonts' ultra-WASPy "A Teenager in Love".

Marley, for his part, was off studying Rastafarianism under the black radical Mortimer Planno, and writing lyrics singing the praises of Ethiopian emperor Haile Selassie, seen here being greeted by crowds of adoring followers on a 1966 visit to the Caribbean; interviewed by Macdonald, Marley's wife and backing singer Rita admits she found it "crazy" that such a little man should be worshipped as the reincarnation of Christ, until she perceived stigmata wounds on Selassie's palms as he waved. The film notes Marley's reluctance to be co-opted by the white Jamaican Michael Manley's government ("He had friends on both sides"), but suggests he was a dreadlocked conciliator who could be recalled from his UK exile in the late 1970s in a bid to bring unity to a Kingston increasingly divided by gang-related political violence.

After One Day in September and the wildly successful Touching the Void, Macdonald has earned his reputation as a blue-chip documentarist, and Marley accordingly arrives bearing the full approval and co-operation of both the Marley estate and Chris Blackwell, the figurehead of Island Records, who doubtless signed on knowing a high-profile retrospective such as this wouldn't do sales of the singer's back catalogue any harm. In truth, Marley finds its groove early on and then sticks to it, rarely deviating from the steady beat of the rhythm guitar. It can't help but liven up when the camera turns towards a pink-haired Lee "Scratch" Perry, whose introduction - pouring kerosene on kindling to set fire to it - may be as good an illustration of the Perry production methods as any, and sparks a (naggingly cursory) deconstruction of the Wailers sound. Still, it was Blackwell, a savvy operator, who finally worked out how to sell Marley to the world, and while he's gracious enough to admit that certain early recordings on Island were "pasteurised" for easier consumption, the narrative line suggests it was he who drove a wedge between the Wailers when they realised they were no longer essential to the Marley sound and image.

Such gripes are handled sensitively, as are the stories of Marley's womanising: Rita, who's had a long time to reconcile herself with her husband's straying, describes herself as more "guardian angel" than wife - the woman he would call whenever he wanted to get the groupies and hangers-on out of his dressing room. As a Marley agnostic, I found a little more of this dramatic meat wouldn't have gone amiss over the 144 minutes, but it's certainly well-assembled: bringing together rare Wailers 7"s and archive concert recordings, it's the very model of a lavish coffee-table documentary, a film that'll look grand sitting next to the 25th anniversary remastering of "Exodus" - which is presumably what fans and the producers alike would have wanted. The answer to my earlier doughnut query was, of course, the ones with jam in. But, like "I Shot the Sheriff" and "No Woman, No Cry", you may have heard that one before, many times.

Marley opens in selected cinemas from tomorrow.