Think of him as an American Davy Graham (for whom he subbed at an UK gig in 1966). Rumor has it that in 1964, Sandy Bull handed his electric guitar to his friend Bob Dylan and suggested he try it.“Re-Inventions,” a collection culled from his Vanguard recordings, tells you all you need to know. Starting in 1962, when he was 21, Bull single-handedly reinvented what guitar music could be. Later he appeared as a guest on Dylan's Rolling Thunder tour.