First you take a self-test in this book to determine your type. Then you can figure out a diet based on relative amounts of certain nutrients you need. Apparently, certain nutrients have exact opposite effect in some people--a high protein, low carb diet may be absolutely WRONG for you. I sure would like to know that BEFORE I decide on a diet plan.
I also like the fact this book includes exercises, breathing exercises and recommendations for supplements and vitamins. The calorie levels are also set so you can pick one that suits your size and sex (not everyone should eat an extremely low calorie diet.) Of course the book also has sample menus, which are always helpful. Finally, the paperback edition is a reasonable size to fit in a purse or in a briefcase, meaning it can go with you anywhere.
I wasn't sure if I was Atkins, Pritikin or NO KIN to any of these (turns out I am mixed, so that is why I had trouble) This book is really excellent and I can recommend it to anyone who wants to lose weight and eat right.