From this article:
Up to 100,000 songs recorded and filmed between 1966 and 1991 by Bill Graham, the US concert promoter, languished in a San Francisco basement for more than 10 years after his death. Then the collection was bought by Bill Sagan, a health company executive turned rock entrepreneur, who is negotiating to secure the stars' permission to release their music. He was in London at the weekend to meet lawyers for British rockers such as Led Zeppelin and The Who.You can browse, and buy, bits of music history from the archive by visiting Wolfgang's Vault.
The archive has unseen footage of a legendary show by The Who in 1973, when drummer Keith Moon collapsed and a student was picked from the audience to finish the show, and the final concert by the Sex Pistols in 1978. It includes unknown performances by Led Zeppelin such as a version of Howlin' Wolf's Killing Floor, which they later rewrote as The Lemon Song, and a tousle-headed Elton John singing his 1970 ballad Your Song.
Luminaries may prefer to forget some of the footage, such as Joe Cocker vomiting on stage and Madonna hitting herself in the face with her chunky necklaces. All were pitilessly captured by Graham's photographers or, in later years, four cameramen.
Graham, born Wolfgang Grajonca in Nazi Berlin, was described by Joplin as the first concert promoter to respect the artists and give them what they wanted -- on and off stage. Normally wary performers such as Frank Zappa and Bob Dylan signed contracts that allowed him to record their concerts at venues he managed in New York and California. Graham hoarded everything, from ticket stubs and backstage passes to psychedelic Jefferson Airplane posters and surplus Duran Duran T-shirts.