Intermediate/Advanced. If you have been working on playing scales, chords, and harmony in general, this set is the next step towards getting your ears and fingers coordinated. This set is a continuation of Volume 3, but in much more depth. Features 23 CD tracks and most go through all 12 keys! Rhythm Section: Jamey Aebersold (p); John Clayton (b); Mike Hyman (d) Suggested Prerequisite: Volume 3 - The ii/V7/I Progression