This book developed from lecture notes that I wrote and rewrote while teaching the graduate course in quantum mechanics at Berkeley many times and to many hundreds of students between 1965 and 2010. It joins a crowded field of well-established quantum mechanics texts. I hope that by virtue of its contents and approach, this book may add something distinctive and be of use to physics students and to working physicists.

I am grateful for the encouragement I have received from scores of Berkeley students and from Berkeley colleagues D. Budker, E. L. Hahn, J. D. Jackson, H. Steiner, M. Suzuki, E. Wichmann, and the late S. J. Freedman, who was once one of my Ph.D. students, then a highly respected colleague, and always a devoted and loyal friend. I thank P. Bucksbaum, A. Cleland, T. Sleator, and H. Stroke for trying out at least part of my lecture notes on students at other institutions and B. C. Regan, D. DeMille, L. Hunter, P. Drell, J. Welch, and I. Ratowsky for their support and friendship. I am sincerely grateful to Vince Higgs, editor at Cambridge University Press, for his crucial encouragement and support. I also thank Sara Werden at Cambridge University Press in New York, and Jayashree, project manager, and her co-workers at Newgen in Chennai, India, for their unfailing courtesy and expert professionalism.