This book started as something of a cult classic, but has exploded in popularity in the past few years, and I'm glad I picked it up, even while the author's writing style left much to be desired as far as sensitivity to cultural diveristy. It's hard not to be offended by some of his generalizations about how various races and each sex play cards. Nonetheless, he's got some very good information about body language and how it reveals the strength of your opponents' hands. It's scary accurate at times, because so much of it is completely involuntary on our part. Leaning forward, leaning back, stacking chips -- these are all actions we don't really think about when we're doing them, but they all mean something (some more than others). And Caro does an outstanding job of explaining just how reliable each "tell" is.
I also would have liked a chapter on online play, because there ARE tells to pick up there, even if they're not body language or verbal cues. How long does someone take to bet? To check? Use of the auto-action buttons? It's an area very ripe for analysis by the right author, especially because online play absolutely dwarfs the number of hands dealt in cardrooms across this country. I only recently started playing online, but was grateful for another post here that led me to pokercroaker.com, which had sign-up bonus codes and site reviews for all the major sites. Good tip. Anyway, despite my mild criticism of Caro's writing style regarding minorities, I still think this is a very good book, and worth a read, if for no other reason than many of your opponents will have read it, so you'll know what they're looking for in your behavior.