Pavlov's Dog is a 1970s progressive rock/AOR band formed in St. Louis, Missouri in 1972. Pavlov's Dog originally comprised David Surkamp, Mark Gahr on lead guitar, Mike Safron, Rick Stockton, David Hamilton, Doug Rayburn, and Siegfried Carver (born Richard Nadler). Mark Gahr left the band and was replaced by Steve Scorfina. On their second album At the Sound of the Bell (1976), Tom Nickeson was added to the line-up on guitar and he took over Hamilton's keyboard position after the album had been recorded as Hamilton left the band. Safron was still a member of the band but did not appear on the second album; former Yes drummer Bill Bruford played as a guest musician. Safron left in the aftermath of this, partially due to his failure to receive a promised credit on the album sleeve and the band's third album featured Kirk Sarkisian on drums.