Pocket Changes I & II, widely used by musicians throughout the world, contains standard progressions (no melodies) to 421 & 381 tunes (respectively). These handy, small-formatted books contain a great deal of musical information that has proven to be very useful for both educational and professional playing situations – tunes played by all jazz musicians, professional and amateur alike in a format that will fit in any case. There are no duplications between volumes and come in concert key only.