We wish to express our heartfelt thanks to all who made this book possible, especially:
Thomas Tombrello, Chairman of the Physics, Mathematics, and Astronomy Division, for approving this project on behalf of Caltech;
Carl Feynman and Michelle Feynman, heirs to Richard Feynman, for their permission to publish their father’s lectures in this book;
Marge L. Leighton, for her permission to publish an excerpt from the Oral History of Robert B. Leighton, and problems from Exercises in Introductory Physics;
Matthew Sands, for his wisdom, knowledge, constructive comments, and suggestions on the manuscript—and for his illuminating memoir;
Rochus E. Vogt, for the ingenious problems and answers in Exercises in Introductory Physics, for his interview with us, and for his permission to use them in this volume;
Michael Hartl, for his meticulous proofreading of the manuscript, and for his diligent work with the errata in The Feynman Lectures on Physics;
John Neer, for studiously documenting Feynman’s lectures at the Hughes Aircraft Corporation, and for sharing those notes with us;
Helen Tuck, Feynman’s secretary for many years, for her encouragement and support;
Adam Cochran, for his consummate skill in navigating the swamp of tangled book contracts and personalities to find a new home for this book, as well as for The Feynman Lectures on Physics; and
Kip Thorne, for his grace and tireless work securing the trust and support of everyone involved, and for overseeing our work.