I did a technical review of this book, and on the basis of that, I wrote a quote for the publisher to stick on the back - which they did. I stand by what I wrote there - if you want to know about XMPP (aka Jabber) then you really do - honestly - need this book.
There are very few people as qualified as Peter, Kev, and Remko to write this book - they've had an enormous part in making XMPP what it is, and it's quite astonishing that they can not only design protocols and write specifications, but they can also turn out a surprisingly light read which covers pretty much every corner of the technology, in huge depth.
I actually liked reading this book - I'm supposed to know it all, but given who wrote it, it's hardly a surprise that there were one or two new things there for me. But above all, I found it enjoyable. Technical books aren't really meant to be a good read, but it's certainly nice when they are.