I thank my family for continuous support. Many friends and colleagues have given me suggestions that helped to improve the book.  I thank all of them and, particularly, Prof. Jean Kovalevsky, who, long ago, introduced me to canonical perturbation theories and Profs. André Brahic, Rudolf Dvorak, Claude Froeschlé, Juan Carlos Muzzio and Bruno Sicardy, who have often invited me to their institutions, allowing me to have time to write. I thank all my students. They have read almost all the drafts of this book and collaborated with valuable comments that resulted in many improvements in the written text. I thank the copy editor Mike Nugent for his invaluable contribution for the editorial quality of this book. During the work on this project, I had the support of USP --
University of São Paulo, Observatório Nacional, Bureau des Longitudes (now IMCCE), Observatoire de Paris-Meudon, Wien Universität, FAPESP -- Research Foundation of the State of São Paulo and CNPq -- National Council for Scientific and Technological Development.



São Paulo, June 2006

Sylvio Ferraz-Mello