A friend sent me this book a few weeks ago and I just thought I'd mention it for anyone interested.  Contrera was a member of the original Mystics and he tells the story of the group's formation and eventual breakup as the hits stopped coming.  Entertwined in the story is a case of manslaughter which winds up with prison time for one member.  Overall it's an interesting read but I found Contrera's so many name references to friends, business acquaintenances and gangsters to at times be confusing.  He also spends a little too much time with giving us mini-biographies of some of the major music performers of the time who the Mystics performed and socialized with.  What I found particularly interesting were things like his story  about touring with the Alan Freed Show and Freed asking the acts to kick in money for gas, not to mention never getting paid for the tour.
For what it's worth I'd give it three stars.  On a personal level I have only found tthree Mystic tunes to be of particular note; of course "Hushabye", "Don't Take The Stars" and "Over The Rainbow".  The rest of their catalogue seems to me to be run of the mill doowop.  Just a humble opinion.