Al Kooper was the group's initial bandleader, having insisted on that position based on his experiences with the Blues Project, his previous band with Steve Katz, which had been organized as an egalitarian collective. Jim Fielder was from Frank Zappa's the Mothers of Invention and had played briefly with Buffalo Springfield. Kooper's fame as a high-profile contributor to various historic sessions of Bob Dylan, Jimi Hendrix and others was a catalyst for the prominent debut of Blood, Sweat & Tears in the musical counterculture of the mid-sixties.