For part of 1966, Peter Van Gelder was bassist in the Great Society, the pioneering San Francisco psychedelic group most famous for featuring a pre-Jefferson Airplane Grace Slick. Van Gelder -- whose name is sometimes spelled "Vandergelder," even in Great Society guitarist Darby Slick's autobiography -- was living in Madison, Wisconsin when he was asked by Darby to come to San Francisco to replace Bard Dupont. Though he wasn't a bass player, he worked (unlike Dupont, apparently) hard to learn the instrument. Van Gelder also played sax and flute, and was into John Coltrane-styled jazz and Indian music as well as rock. His influences were instrumental in making the band more eclectic and innovative than it had been while Dupont was in the lineup.
Examples of Van Gelder's exotic touch can be heard on the Great Society's version of "White Rabbit," on which he plays soprano sax, and on their cover of "Nature Boy," on which he plays flute (and Grace Slick plays recorder). He also wrote a couple of the band's more impressive songs, "Grimly Forming" and "Arbitration," which appear on their live 1966 recordings (reissued in a variety of forms, including the Columbia CD Collector's Item). These were multi-sectioned songs in which the key changes lent themselves to counterpoint riffs and modal improvisation, elements that were novel in any rock at the time, and touchstones of the psychedelic sound.
Van Gelder and Darby Slick became progressively more interested in studying Indian music as 1966 unfolded, one factor that led to the breakup of the Great Society late that year. Van Gelder is in the lineup for the live recordings on Collector's Item, although the studio material on Born to Be Burned, a compilation released by Sundazed in 1995, was done before he joined.