It is a pretty good book, with a couple of caveats.  If you're still using a conventional grip, or you're a big cranker, it probably won't be much help.  Another thing is that I would suggest videotaping yourself on the lanes now before you change anything, and then change one thing at a time in your practice sessions that you've picked up from the book.  If you try to change everything at once you're in for some serious rebuilding time to get back to where you were.  Some stuff won't work for you, and it might be hard to figure out why.  For me, I finally figured out that when I attempted to use his "up and over" pushaway tip I would block my view of my spot and drift to one side, rather than heading straight up the approach.  I hold the ball lower now, but that's what works for me. Good luck.
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the 3 is silent

The book has been really helpful to me. Like Shawn said, I also go back to the book whenever I bowl poorly for a couple of weeks. It never hurts to review the basics whenever you get into a funk. I really believe the over/under technique played a major role on me getting my first 300 this past season.

It is one of only three or four bowling books I would recommend.  It is the best book I have seen trying to explain execution and the physical in a way that golf and other sports are taught.

While the name dropping is irritating, for a number of people that is the only way to get their attention to the fact that his observations are grounded in fact.
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"It's just a carry contest."