Book/CD. These tracks were originally recorded as a standard listening CD. But because of the high quality of the recording and the intense groove, it was suggested that we release the tracks with lead sheets so that others - both students and accomplished players - could enjoy them, as well. Thus, a new kind of play-along was born; a play-along designed for performance and not education. This is precisely what makes it so fun to play. Nothing is lessened or "watered-down" to facilitate graduated, comprehensive learning. There is nothing to do but to jump in and hang on; just as if you are in the studio when the red light comes on.