In April 1966, the duo of Graves and pianist Don Pullen played at Yale University. As John Corbett writes in the liner notes, "This performance was something of a turning point for Graves. Until then he had been working in other people's bands or collective ensembles. He was phenomenally busy. In 1965 alone, he recorded with NYAQ (two LPs), Giuseppi Logan Quartet, Paul Bley Quintet and Lowell Davidson Trio, and he made his first recording released under his own name, Percussion Ensemble. Every one of these is important in its own way, but none of them quite anticipate how radical was the music that he and Pullen would unleash that evening in New Haven."
Originally released on the artists' own Self-Reliance Program label, this legendary one-night performance would be split into two volumes: In Concert At Yale University and Nommo. While rooted in African rhythms, Graves' music has its own sense of time. As the drummer stated in a 1966 DownBeat interview, "Time was always there, and the time I see is not the same as what man says time is. It works by impulsion."