The 70-year-old svengali passed away in California on Monday (12Jan15).
Thompson took over management of the beloved rock group in 1968 and remained with the act during a string of name changes. He also managed spin-off group Hot Tuna, as well as the solo careers Paul Kantner, Jorma Kaukonen and Grace Slick.
He was part of the formation of the San Francisco-based band because he shared a room with the group's original singer Marty Balin. He took over management duties from rock legend Bill Graham.