If “Lambert and Stamp” were nothing more than a first-rate musical documentary about The Who, that would be a fine accomplishment. But James D. Cooper’s film is much more than that. Technically it’s a pretty dazzling collage of material, mixing reams of archival footage and exceptionally revealing interviews. But more importantly it’s a perceptive, ultimately quite moving tribute not just to a band but to an extraordinary man who was one of the major players in the group’s history, despite the fact that he never held an instrument and is no longer around to tell his own story.

That was Kit Lambert, who together with Chris Stamp (the brother of actor Terence), friends from very different backgrounds but both aspiring filmmakers, decided in 1964 to pursue an unusual project that would provide the material for a breakthrough documentary. They would find a rock band, become its managers, and then follow its rise, recording everything on celluloid as they went along. That project resulted in a mass of archival material, which Cooper supplements with news excerpts to provide not only a stream of evocative black-and-white footage focusing on the band itself, but on the milieu of the Swinging Sixties in which it emerged into the spotlight.

Stamp, who died in 2012 after completing the interviews that make up a major part of the picture (his brother also speaks on camera about their early, rather difficult lower middle-class days), tells us a good deal about himself in genial, often self-deprecatory reminiscences, but his major emphasis is on Lambert, the Oxford-educated swell (among the segments are a few showing him giving interviews in French and German during The Who’s tours) who was the son of Constant Lambert, a classical composer and conductor who died when his son was sixteen. (Ballet star Margot Fonteyn was his godmother.) A chain-smoking intellectual (observer Richard Barnes says that people joked he’d only used one match in his life, firing up each cigarette successively from the last), he was also openly gay at a time when homosexuality was still a crime in Great Britain. It was he who found The Who, then called High Numbers, playing to gyrating crowds in Barnes’ raucous London club, and secured the job of co-managers for himself and Stamp, though they had no experience whatever.

Still they succeeded beyond their wildest hopes, and the rise of the group, characterized by their onstage antics in destroying their instruments, is covered in brisk, engaging detail. Stamp provides much of the story, but more is offered by Pete Townshend and Roger Daltrey, the surviving members of the group. And though they offer reminiscences about bassist John Entwistle and drummer Keith Moon, the focus inevitably comes back to Lambert as all agree on how he cultivated Townshend’s musical talent while leaving the others—particularly Daltrey—largely to their own devices.

Despite some friction within the band (Daltrey admits, for example, that he allowed himself to be goaded into violence by Moon), the overall situation among the six men—the quartet on the stage, along with Lambert and Stamp—seems to have remained reasonably solid until “Tommy” intervened. There was some dispute over how great a role Lambert had played in the creative process of the “rock opera,” but the real problem arose when Townshend passed over Lambert and Stamp as producer-directors of a film based on the album in favor of Robert Stigwood and Ken Russell. For the management team, which had already expanded their work into record production, the movie would have been the fulfillment of the filmmaking dream they’d begun with in the first place.

For Lambert, who was already involved in drug use, this accelerated a decline that ended with his death in 1981. His fate lends a deep sense of regret to the latter sections of the film, but interviewees Stamp, Townshend and Daltrey all emphasize the remarkable nature of his earlier years rather than the problems of his later ones.

Cooper’s dedication and skill, as both director and cinematographer, obviously deserve enormous credit for bringing so much material together so well. But kudos are also due to editor Christopher Tellefsen, whose cunning use of swift cuts, image overlaps and graphics—as well as bleeding color from some of the interview segments to align them visually with the black-and-white archival footage surrounding them—makes for a quite vivid experience. The result is not only a music documentary that’s worthy of its subject, but an exceptional work of pure filmmaking.