This volume was prepared in conjunction with a Symposium held in Berkeley June 5 7, 2005, as a tribute to Professor Pravin Varaiya. The contributions represent most of the lectures given at the meeting. The Symposium brought together former students, collaborators and friends from throughout the world to celebrate Pravin s career as he approached the memorable occasion of his 65th birthday. The authors, speakers, organizers, supporters and attendees of the Symposium are very pleased to dedicate this work to Pravin, to congratulate him on his many seminal contributions, and to thank him for...