I've decided to give Dr. Alan Schoonmaker the nickname Dr. Poker, since this book - combined with all his previous books - form an amazing body of work that is indispensable for the health of all poker players. If there's a leak in your game, your poker personality, your internal attitude towards poker or your approach to the game, Dr Poker is the man to help you fix it. And because his books are not about strategy but personal insight, they are rather timeless, and players at just about any level of play - from beginner to expert - will likely find a lot of information to improve their performance at the poker table.
Since different problems pop up in a player's psyche at different stages in their game play, this book (like his others) is an invaluable reference tool that requires constant re-reading to maximize its value. A first reading may isolate and fix a few problems with your poker attitude. Later readings may identify other problems that didn't exist the first time, but have developed since then. Like physical health, poker health is constantly changing and evolving and this book is the perfect tool as a constant reference guide to refer back to repeatedly.
This book has played a very major role in improving my poker health and I expect it to continue doing so for as long as I play poker.