I thank everyone who supported me and helped me write this book, from the many authors who inspired it to my family, including my daughters, Ana Sofia and Helena, Mariana and Clara, and my parents, Arlindo and Amália. I hope they will, one day, be able to read this book and to understand some of the more radical ideas set forth in it. I fear, however, that for my parents this may turn out not to be the case. Given the nature of science and technology, we become rapidly obsolete and unable to understand new developments. Sometimes things change just too fast for us to follow them.
I also thank the institutions at which I was privileged to work, including Instituto Superior Técnico, the University of California at Berkeley, Cadence Design Systems, CERN, and INESC. They were, for decades, my home away from home.
Someone has said a book is never finished, only abandoned by its author. I abandoned this book at the end of my recovery from a fairly serious surgical intervention. The time I needed for the recovery enabled me to bring to fruition what had been, until then, little more than a dream. I owe this possibility to the many friends who helped me and also to the talented surgeon who operated on me, Dr. Domingos Coiteiro.
The overall organization of the book and the actual text owe much to the many friends and colleagues who patiently read and commented on drafts. I would like to thank, in particular, Jonas Almeida, Miguel Botto, Luís Pedro Coelho, Tiago Domingos, Mário Figueiredo, Alexandre Francisco, Vítor Leitão, Pedro Guedes de Oliveira, Amílcar Sernadas, Manuel Medeiros Silva, Larry Wald, and the anonymous reviewers for many useful suggestions and corrections. I also thank Miguel Bugalho, Afonso Dias, Patrícia Figueiredo, Alexandre Francisco, Bobby Kasthuri, and Richard Wheeler for the material they contributed for use in the book.
I thank Pedro Domingos for suggesting the MIT Press as the right publisher, Marie Lufkin Lee for believing in the project, and Kathleen Hensley for handling all the technical matters related to the preparation of the manuscript. I am especially indebted to Paul Bethge, the manuscript editor, who greatly contributed to the readability of this book with his suggestions, corrections, and improvements.
During the writing, as well as during the years that preceded it, my wife, Ana Teresa, was my support and my strength, with a dedication that was clearly above and beyond the call of duty. I thank her from the bottom of my heart, and dedicate this book to our future together.