The Who spent most of 1969 and 1970 on the road, playing their rock opera, Tommy, as the centerpiece of epic concerts. They’d become a fearsomely powerful live band, as fluid as they were brutal: four wizards at separate corners of the stage, raising a golden demon together. The original version of Live at Leeds, recorded at a college gig on Valentine’s Day, 1970, was three cover songs and three transfigured Who standards, packaged to look like a warts-and-all bootleg LP (which explained the crackles from a faulty cable). As singer Roger Daltrey later put it, it’s “the end of a two-and-three-quarter-hour show…it’s just the jamming bit at the end.” Tommy itself was omitted, although some of its riffs show up in the course of a 15-minute jam that evolves out of the proto-punk headbanger “My Generation.” Later editions have gradually added the other 27 songs played that night. Douglas Wolk