A history lesson in Deep Purple. The actual quality of the CD set is very good, so no concerns there. The contents provides a broad range of some of the other material they have been involved with. There are different versions of well known tracks performed by themselves as well as other artists performing them. As mentioned in another review the William Shatner tracks, ....well perhaps an acquired taste, but ' New Frontiers and to Boldly Go' seem to be the order of the day, well worth buying, and all the tracks in one place.