The Beatles and Duke Ellington's Orchestra stand as the two greatest examples of collaboration in music history. Ellington's forte was not melody--his key partners were not lyricists but his fellow musicians. His strength was in arranging, in elevating the role of a featured soloist, in selecting titles: in packaging compositions. He was also very good at taking credit when the credit wasn't solely his, as in the case of Mood Indigo, though he...