When the Beatles cut old rock n' roll, they were recording music still in their performing repertoire, and besides, they never thought of the music as old.

Elton John can be a master of the sleight of hand. The arrangements make it seem like there are substantial melodies underneath the tracks - but almost nothing demands repeated listenings. Similarly, he always sounds like he's singing up a storm, but his voice glosses over the material, reducing most things to an uninteresting sameness.

The Rolling Stones are constantly changing, but beneath the changes they remain the most formal of rock bands. Their successive releases have been continuous extensions of their approach, not radical redefinitions, as has so often been the case with the Beatles.

Joni Mitchell seems destined to remain in a state of permanent dissatisfaction - always knowing what she would like to do, always more depressed when it's done.

Sly Stone doesn't make good albums: only good records. His style is so infinite and revolves around so many crucial aspects that it has only come together perfectly on a handful of his singles.

To her audience, Janis Joplin has remained a symbol, artifact and reminder of late Sixties youth culture. Her popularity never derived from her musical ability, but from her capacity to link her fantasies of freedom and immortality with ours.

Ringo Starr may not have much of a voice, but when he sang a song on a Beatle album, it had its own special charm.