Another great book from this author - inspiring, motivational, precise, practical...I could go on. Dr Yang's book lives up to his reputation as a true master. Everyone knows you can't learn any full system of martial arts from a book, but this (and the author's Analysis of Shaolin Chin Na) book is absolutely jam-packed with clear photographs, incredibly thorough yet easy-to-understand narrative, and a wealth of useable techniques, so integrating the knowledge in this book into your own training, regardless of system, should really be foolproof.
There are comments below that it fails to focus on entry techniques. Well, the nature of any art dictates you will have to bridge with your opponent at some point, so do this according to your own system. What this book will do is massively enhance your options when there.
Honestly, I would be shocked if you didn't think this book was worth one hundred times what you paid for it!