In music, as you develop a theme or musical idea, there are many points at which directions must be decided, and at any time I was in the throes of debate with myself, harmonically or melodically, I would turn to Billy Strayhorn. We would talk, and then the whole world would come into focus. The steady hand of his good judgment pointed to the clear way that was fitting for us. He was not, as he was often referred to by many, my alter ego. Billy Strayhorn was my right arm, my left arm, all the eyes in the back of my head, my brainwaves in his head, and his in mine.
Duke Ellington