This book was an excellent guide to the world of XMPP. Although most of this information is available on the Internet, it is often disjointed, conflicting, and difficult to week through. However, Jack was able to help make sense of it all, and leads the reader step-by-step through integrating XMPP with the Web.If you are struggling to understand XMPP and create a chat client for your site, this book is an essential, which I highly recommend. In fact, I used many of the ideas found in the book to create DXMPP, a module for a Facebook-like chat client for Drupal. This book is definitely the go-to for web developers wanting to learn XMPP.