American jazz bass guitarist and composer, born october 4th, 1940. Initially he played double bass (most notably in the trio with Jimmy Giuffre and Paul Bley and with Art Farmer); in the seventies he switched to electric bass guitar exclusively.
In 1960 he left his composition studies at Yale, but began writing music professionally in Art Farmers quartet (he joined it in 1964).
Among notable musical associations is his work with Gary Burton, Carla Bley (whose husband he is) and John Scofield.
His style involves intricate solos in the upper register of his instrument; he was one of the first to adopt he High C string on the bass guitar.