I will start this review by saying what this book is *not*. It is *not* primarily about "Climategate" ie the e-mails published last November. Despite the book's subtitle, only towards the last 10% or so of the book does it even get into the issue of Climategate's e-mails - apparently an update to a book that was essentially ready by the time the e-mails became public.
What this book is: a prime example of journalism, and historical narrative, when applied to a very specific scientific issue. I firmly believe this book will be studied by historians for generations to come when they try to understand the bizarre episode of the hockey stick graph. I think the book works at three levels: (1) it is a highly technical, and fully referenced - yet still easily accessible - explanation of the scientific (or would-be scientific) background of the hockey stick and its successors, and of why it was ultimately an illusion (not to say: outright fraud); (2) it is a historical narrative very clearly explaining the sequence of events and their connections; and (3) at another level, it is the history of how one retired mining consultant, Steve McIntyre, with few resources apart from his brain, his free time, and his computer managed to take on an entire "scientific" establishment (more accurately, scientific-political) and emerge vindicated despite all attempts to ignore or even ridicule or villify him.
The only criticism I will make of this book (not enough to make me give it less than 5 stars) is that it could have been edited better. For instance, US Representative Joe Barton is referred to as "Senator" at least once, and references to "see page xy" are occasionally incorrect. Such errors are, however, very rare and in no way prevent the reader from following the book's arguments.