This text builds a solid introduction to the concepts and techniques of quantum mechanics in settings where the phenomena treated are sufficiently simple that the student does not face two fundamental difficulties simultaneously: viz, that of learning quantum mechanics and that of learning how to assess the validity of models or the reliability of approximations. The treatment thus confines itself to systems that can either be solved exactly or be handled by well-controlled, plausible approximations. With few exceptions, this means systems with a small number of degrees of freedom. The exceptions are a first pass at many-electron atoms, the electromagnetic field, and the Dirac equation. (The inclusion of these last two topics reflects the now widely-held belief that every physicist should have at least a nodding acquaintance with these cornerstones of modern physics.) Born in Vienna, Kurt Gottfried emigrated to Canada in 1939 and received his Ph.D. in theoretical physics from MIT in 1955. He is professor of physics at Cornell University, and had previously been at Harvard University, the Massachusetts Institute of Technology, and at CERN in Geneva. He is the co-author of Concepts of Particle Physics (with V.F. Weisskopf), and of The Fallacy of Star Wars and Crisis, Stability, and Nuclear War. Gottfried has an active interest in arms control and human rights and is a founder and currently the Chair of the Union of Concerned Scientists.

This classic text provides a comprehensive exposition of the concepts and techniques of quantum mechanics. The phenomena treated are sufficiently simple to allow the student to readily assess the validity of the models so that attention is not deflected from the heart of the subject. To that end, the book concentrates on systems that can either be solved exactly or be handled by well-controlled, plausible approximations. With few exceptions, this means systems with a small number of degrees of freedom. The exceptions are manya "electron atoms, the electromagnetic field and the Dirac equation. The inclusion of the last two topics reflects the belief that every physicist should now have some knowledge of these cornerstones of modern physics.

This new edition has been completely revised and rewritten throughout, but retains the clarity and readability of the first edition.

Born in Vienna, Kurt Gottfried emigrated to Canada in 1939 and received his Ph.D. in theoretical physics from the Massachusetts Institute of Technology in 1955. He is a professor emeritus of physics at Cornell University, and had previously been at Harvard University and at CERN in Geneva, Switzerland. He is the coauthor of Concepts of Particle Physics (with V.F. Weisskopf) and of Crisis Stability and Nuclear War. Gottfried has done research in both nuclear and particle physics; he has an active interest in arms control and human rights and is a founder and currently the Chair of the Union of Concerned Scientists.

Tung-Mow Yan, originally from Taiwan, received his Ph.D. in theoretical physics from Harvard University in 1968. He has been a member of the Cornell University faculty since 1970 afterspending two years as a research associate at the Stanford Linear Accelerator Center. He has conducted research in many areas of elementary particle physics.