There was one thing missing from Ian Thullier's excellent, lovingly crafted documentary Rory Gallagher: Ghost Blues and that was an insight into the brilliant, trail-blazing guitarist and singer's private life.
Cynics might assume this was because the film, which featured Rory's younger brother, Donal, as both one of the executive producers and a frequent on-screen contributor, was the officially sanctioned version of his life. Wrong.
This was no sanitised PR job in the manner of the tepid The Stones in Exile, which was recently screened on BBC2.
The reality is much more prosaic: Rory Gallagher simply didn't appear to have a private life.
The music, the playing, the near-constant touring, these constituted both his outer and his inner existence. It was what he lived for and it left no space for girlfriends, wives, or children.
His beloved guitar, a 1961 Fender Stratocaster he bought second-hand in a music store after it had been discarded by a showband musician, was his mistress and his best friend. "It became his partner for life," said Donal. "In his own way, he was living the bluesman's life. He didn't know how to make a commitment to somebody else."
"He was built for touring," added Cameron Crowe, the Rolling Stone journalist-turned-film director who discovered Rory's first, self-titled solo album through a cloud of dope smoke at a Greenwich Village party in the 1970s.
Ultimately, it was also what he died for, 15 years ago this month, aged 47, having developed an infection following an otherwise successful liver transplant. Life on the road, fuelled in his last years by a combination of heavy drinking and ill-advised prescription drugs (Rory, said Donal, was desperately naive about how he used medication), eventually took its toll.
Ghost Blues certainly didn't flinch away from its subject's sad and early death; Donal's description of visiting his brother at his London apartment, his once-lithe body beginning to bloat and his skin "saffron", was frank and moving.
Yet the film didn't dwell on it, either, because there was so much else to dwell on: his electrifying stage presence (recalled here through a wealth of wonderful archive footage), his absolute devotion to the blues, and his disdain for those who sought to smooth out and commercialise him
"I'll never play with an orchestra or a brass section," he said in an audio clip. "I'm not going to become Bryan Ferry or The Police." And there was his unrivalled musicianship.
"I once saw him change a string without stopping a song," marvelled Johnny Marr, no slouch on the guitar himself. Bob Geldof first saw Rory at the Isle of Wight Festival ("I was there selling drugs") and was mesmerised.
"It was the first time I saw a blues band that were actually blues. I always thought of him as a priest with long hair. His guitar was his chalice and his prayers were the blues."
"He was an album guy and a great live performer," said Bill Wyman, who recalled the time Rory almost became a Rolling Stone. "Mick and Keith felt he wasn't the right type of performer," he added, which was a coded way of saying Jagger and Richards' warring egos wouldn't have been able to handle the competition from such a staggeringly talented natural frontman.
Geldof put it more bluntly: "Rory could never have just put up with the b*llocks of Mick and Keith."
There's no denying that Rory's musical integrity -- he refused to release singles and at one point dropped an album he was unhappy with into a bin, in front of assembled record company suits -- damaged his wider commercial potential.
His band Taste, whose albums were shooting up the charts faster than those of the bands they were supporting on tour, broke up sooner than they should have -- which, suggested The Edge, was something of a motif for Rory's career.
Then again, which would you rather have: the bullsh*t or the wonderful Gallagher legacy? Rory had no time for the bullsh*t and neither did this splendid film.
Rory Gallagher: Ghost Blues ****