I suppose this book does a thorough job of covering all aspects of a fitness regimen for a golfer including stretching, weight training, diet and injury prevention and it often offers golf specific exercises. If you've never really been on a consistent exercise program and don't have any other fitness books and you play golf, then I guess this book may be an option for you.
But I have two main problems with this book:
(1) First, this really is just a general fitness routine book that could be applied to almost any sport, or if you were just interested in general fitness, no sport at all. Yes, the book does approach the exercises from a golfer's perspective, but a perspective is all. None of the weight training exercises or stretches are any different from what you would read in any other general fitness book, and you shouldn't be performing them any other way lest you hurt yourself. As far as the eating tips, if the saturation of news reports in the last decade on eating a low-fat, high-fiber diet haven't convinced you to eat well, then one chapter in this book ain't gonna do it either.
(2) I think the premise of the book and specifically the book title is just wrong. It has been shown through application and studies (see my review of The Physics of Golf on this site) that distance off the tee is not affected that much by moderate amounts of muscle gain, especially the amount that one could get by lifting. Golf is a game of fluidity and vectors, not solely raw power. Some of the longest hitters on the tour now (2003) are some of the skinny young kids on the tour. I agree with the author that stretching is key, but you don't need this book for that (see my review of Bob Anderson's "Stretching").
I'm confident most people already know the basics of a good golf fitness regimen: eat healthfully, jog 3 times a week and stretch all parts of your body well before and after a round or hitting the driving range.