Quicksilver Messenger Service is an American psychedelic rock band formed in 1965 in San Francisco. The band achieved wide popularity in the San Francisco Bay Area and, through their recordings, with psychedelic rock enthusiasts around the globe, and several of their albums ranked in the Top 30 of the Billboard Pop charts. They were part of the new wave of album-oriented bands, achieving renown and popularity despite a lack of success with their singles. Though not as commercially successful as contemporaries Jefferson Airplane and the Grateful Dead, Quicksilver was integral to the beginnings of their genre. With their jazz and classical influences and a strong folk background, the band attempted to create an individual, innovative sound. Music historian Colin Larkin wrote: "Of all the bands that came out of the San Francisco area during the late '60s, Quicksilver typified most of the style, attitude and sound of that era."
The band's members included John Cipollina, Gary Duncan, Greg Elmore, David Freiberg, Nicky Hopkins, and Dino Valenti. Valenti drew heavily on musical influences he picked up during the folk revival of his formative musical years.