It was one of Ellington's many collaborations in the early 1960s with musicians such as Count Basie, Louis Armstrong, Coleman Hawkins, Max Roach, and Charles Mingus, and placed him with a quartet (in this case, saxophone, piano, bass, and drums), rather than a big band. The quartet was filled out by the bassist and drummer from either of their bands. The album featured Ellington standards (e.g., "In a Sentimental Mood"), new Ellington compositions, and a new Coltrane composition ("Big Nick").
I was really honored to have the opportunity of working with Duke. It was a wonderful experience. He has set standards I haven't caught up with yet. I would have liked to have worked over all those numbers again, but then I guess the performances wouldn't have had the same spontaneity. And they mightn't have been any better!