Acknowledgements
Without the encouragement we received from Stephen Hayes we would not have written this book. He was the first to see the need for a book on the IMS that provided the IETF perspective in addition to the 3GPP and 3GPP2 perspectives. In addition, he and Allison Mankin did an outstanding job coordinating the IMS standardization from 3GPP and from the IETF, respectively.
Once we decided, pushed by Stephen, to start writing this book, our management in Ericsson Finland fully supported us in this endeavor. In particular, Stefan Von Schantz, Christian Engblom, Jussi Haapakangas, Rolf Svanback, and Markku Korpi understood from the beginning the importance of the IMS and of spreading knowledge about it.
Our technical reviewers helped us fix technical errors in early versions of the manuscript. Andrew Allen provided useful comments on the whole manuscript. Harri Hakala, Arto Mahkonen, Miguel Angel Pallares, Janne Suotula, Vesa Torvinen, Magnus Westerlund, Brian Williams, Oscar Novo, Jari Urpalainen, Joël Repiquet, Mari Melander, Hannes Tschofenig, Javier Pastor, Jan Holm, Ari Keränen, and Vesa Lehtovirta provided suggestions on different parts of the book. Takuya Sawada and Takuya Kashima performed a thorough review of the manuscript during its translation to Japanese. Anna Reiter provided guidance on language and writing style.
Our editor at John Wiley & Sons, Ltd, Mark Hammond, believed in this book from day one and supported us at every moment.
