WE ALL STAND ON THE SHOULDERS OF GIANTS, and I am fortunate to have stood on many friendly ones throughout my career and while writing this book. Thanks to Carol Long and Ed Connor for the encouragement, handholding, reminders, and patience that every author needs. Thanks also to Jason Salas who not only encouraged me on this project but made the appropriate introductions. Thanks to Dave Cridland for his work ensuring the technical quality of this book and his tireless humor. I'm hugely indebted to Peter Saint-Andre, patron saint of XMPP, and the rest of the XMPP Standards Foundation members for their advice, criticism, and friendship over the years. My colleagues at Collecta and Chesspark also deserve credit for all their friendship, support, and advice, without which I could not have written this book. Finally, the biggest thanks of all to my wife; not only did she encourage me in this project and put up with my long hours and absence, she also worked hard as my first reader and made many helpful suggestions to the text.