Looking at the title of the book, I felt the same way that I did the first time I saw a For Dummies book on a topic in my field. Having said that, I would classify this as exactly that. A for dummies book for EXPERIENCED players.
If you are ready to get serious about your poker and become a winning player, I highly recommend this book. I can not count the number of times where I saw an obvious chapter title like, you play too many hands or you need to play position and would nod, yeah yeah. I would then get to the chapter and still be nodding my head, and then BAM - my jaw would drop open as they recounted a session that fit me to a T. Not just once, but over and over again. This book has helped me analyze my play and indentify some big holes I had thought I had overcome long before.
In todays internet poker age, there are a lot of decent ABC poker players as well as a lot of wild poker maniacs. This book goes a long way towards helping you analyze your own poker style as well as understand others on a much deeper level. I can not recommend it enough.