Nermeen Ismail provided a cover-to-cover review of the book, lending considerable expertise in video and voice over IP. Jesse Herrera also provided a full review, verifying all parts of the text in minute detail. The authors are particularly grateful to Stuart Taylor for providing a number of suggestions and comments on the introduction and architecture chapters; to Tripti Agarwal for taking time to review the H.323 section and provide her insight on CallManager signaling implementation details; to Judy Gulla for doing a thorough review of the SIP chapter and providing valuable comments; to William May for reviewing the media control chapter; and to Dan Wing, who was instrumental in reviewing the security chapter.