In a remarkable clip in Jeff Stein’s 1978 documentary on The Who, we see the band in their early-1970s incarnation, Pete Townshend in his white utility suit and Doc Martens (two decades before it was hip). They deliver a roaring version of jazz singer Mose Allison’s “Young Man Blues” that is as good a piece of live rock & roll as you’re ever likely to hear. Somewhere between blues, R&B and heavy metal, it crunches and thunders with an exhilaratingly distinctive sound, a synthesis of the band’s diverse musical sensibility distilled into a few short minutes that could be used to illustrate the sheer visceral power of rock & roll in any decade.

That clip is one of many memorable ones gathered in a very loose, very entertaining film which concentrates primarily on the music rather than on probing too deeply into the band’s personalities. There are some wonderful examples of the band’s incarnations, however, and we gain brief glimpses of Pete Townshend’s metamorphosis from an angry young man, oozing punk attitude, to an articulate artist who considers pop music “crucial” to the progression of art.

The performances are almost all powerful, with Pete Townshend, bassist John Entwistle, singer Roger Daltrey and drummer Keith Moon roaring and screaming like a locomotive barely in control, displaying a supernatural gift for dynamics. On a bad night, The Who were perhaps the best live band in rock music. On a good night, they were transcendent.

Stein’s film occasionally disappoints: two performances filmed specifically for the film – “Baba O’Reilly” and “Won’t Get Fooled Again” – come off like weak self-parody, and we get one too many montages of Townshend and Moon smashing their instruments. It also would have been nice to let some of Townshend’s interview clips play a bit longer – Townshend says he hated Woodstock, but we never hear why – but such complaints are minor. There’s so much here to enjoy, not the least of which is hearing Townshend’s gloriously crafted pop in its best element – live.