Gary Duncan was a founder member of the legendary San Franciscan band Quicksilver Messenger Service. Between 1965 and 1975 the band played literally thousands of concerts and attracted massive critical acclaim and along with The Grateful Dead and Jefferson Airplane were one of the most influential bands to come out of San Francisco in the sixties. Gary played on many albums released by Quicksilver Messenger Service including Quicksilver Messenger Service, Happy Trails, Quicksilver and Solid Silver. Although the band effectively split in the mid seventies Gary has quite often along with David Freiberg reformed Quicksilver Messenger Service and toured the world usually with Jefferson Starship which also numbers David Freiberg as a member.

For a period from the mid eighties through to the mid nineties and beyond Gary Duncan led his own band Quicksilver and released a number of albums. These albums are now being made available again once more at the behest of Gary Duncan having been unavailable for some time.

Six String Voodoo was originally released in 2008 and features six new Gary Ducnan songs including Katmandu, Pharaoh's Dance and Don't Be Lonely alongside a cover of the Thelonious Monk song Round Midnight. The album whilst giving the impression of a Gary Duncan solo album is in effect the new Quicksilver.