Special thanks to Omri Gazitt for his continued support and multiple suggestions; to Alan Geller, Jim Johnson, John Justice, and Rodney Limprecht for thorough reviews and excellent insights; to Dan Simon for his description of common security attacks; and to Chris Kaler for his guidance and multiple revisions of the sections on security. John Shewchuk's contributions to the architecture section were also a great help. Thanks to Phil Bernstein, Vittorio Bertocci, Shy Cohen, Paul Cotton, Chris Keyser, John Lambert, David Langworthy, Andrew Layman, Brad Lovering, Jeffrey Schlimmer, Scott Seely, Matt Senft, Satish Thatte, Marvin Theimer, Jorgen Thelin, and Hervey Wilson for their reviews and encouragements. Finally, thanks to Don Box for his regular assistance with every aspect of this book.Last but not least, the following individuals have participated in defining the Web services architecture: Tony Andrews, Bob Atkinson, Keith Ballinger, Don Box, John Brezak, Allen Brown, Luis Felipe Cabrera, Erik Christensen, George Copeland, Michael Coulson, Giovanni Della-Libera, Brendan Dixon, Mike Dusche, Colleen Evans, Max Feingold, Henrik Frystyk Nielsen, Praerit Garg, Omri Gazitt, Alan Geller, Josh Gray, Martin Gudgin, Destry Hood, Efim Hudis, Tomasz Janczuk, Jim Johnson, Ryan Johnson, John Justice, Gopal Kakivaya, Chris Kaler, Johannes Klein, Scott Konersmann, Brian LaMacchia, Dave Langworthy, Andrew Layman, Paul Leach, Al Lee, Rodney Limprecht, Joe Long, Steve Lucco, John Manferdelli, Ashok Malhotra, Jonathan Marsh, Steve Millet, Angela Mills, Stefan Pharies, Scott Robinson, Yordan Rouskov, Sujay Sahni, Jeff Schlimmer, Oliver Sharp, John Shewchuk, Yasser Shohoud, Dan Simon, Jeff Spelman, Keith Stobie, Satish Thatte, Robert Wahbe, Elliot Waingold, Richard Ward, Hervey Wilson, Kenny Wolf, and Eric Zinda.