There are many books that will teach you how to play poker, right from the fundamentals up to advanced play. This book is different to those books (and should probably be read after you have read one of them). It is intended to help you develop the correct mental approach to the game.
Whatever stage of development your poker game is at I strongly suspect that your overall game would benefit from reading this book. A change in the way that you approach the game could very well add to your winnings at the table. Those who struggle with tilt issues or seem to be forever complaining about bad beats will find the book particularly enlightening.
If you are looking for something different in your poker literature then this is it.