Paul Bley, CM was a Canadian jazz pianist known for his contributions to the free jazz movement of the 1960s as well as his innovations and influence on trio playing and his early live performance on the Moog and ARP synthesizers. His music has been described by Ben Ratliff of the New York Times as "deeply original and aesthetically aggressive". Bley's prolific output includes influential recordings from the 1950s through to his solo piano recordings of the 2000s.

Charles Edward Haden was an American jazz double bass player, bandleader, composer and educator whose career spanned more than 50 years. Building on the work of predecessors such as Jimmy Blanton and Charles Mingus, Haden helped to revolutionize the harmonic concept of bass playing in jazz, evolving a style that sometimes complemented the soloist, and other times moved independently, liberating bassists from a strictly accompanying role, to allow more direct participation in group improvisation.