This is a book that comes around only once every couple of years. As a poker book, it's one that comes around even longer than that.
I was going to begin this review noting just how technical it was, but that might not be the right word since it's also so accessible. What I will say is that this book isn't for most players. Most players don't want to know the rationale behind every move that's played at the table (their's or others'), they just want to get "better". This book, sitting at nearly 500 pages, isn't a light book you can flit in and out of; it's a book that will teach you, truly, how to play great poker. You can read it like any other book, but the quality of the content almost demands you treat it like a textbook - taking notes, earmarking pages, underlining the crap out of it. The density of information is actually quite astounding, and will require more than one read-through to grasp everything. Hell, I made tonnes of notes on the first read-through, and there are subtleties I'm noticing only on the second.
The written style is great, easy going, and mature - instead of telling you, Ms Duke *shows* you, explaining why certain players play certain hands, why they might decide to raise instead of call in certain situations, and your different options in responding to their actions depending on the strength of your hand, texture of the board, tilt, etc. Many other books give hard and fast rules, and though if feels like there are some in this book (masked with verbs like 'consider') they make sense in the context of 'making the right decision'. E.g. if you're holding 72o with three callers post-flop you should 'consider' folding. You don't have to, but there's a very, very high chance you'll lose that hand even if a 7 lands on the river; therefore that 'rule' of ducking out there isn't one of those nasty inflexible ones, it makes sense, and why it does is always explained fully, usually with examples.
This book hasn't affected my win-rate much, it was already fairly high, but I am a much better player for having read it. I'm making vastly better decisions, and can now account for all of my actions on the table. I'm also reading people's actions better, rationalising their decisions, and guessing right much more often.
Like I've said, it's rather accesible for a technical book, but by no means is it an 'easy' read. Treat it like a course, read 50 pages every other day, take notes, and put it into practice, and you'll soon be out performing your usual table-mates.