In the new edition, supplements, additional explanations and cross-references have been added at numerous places, including new formulations of some of the problems. In all these additions I have attempted not to change the compact character of the book. The present third English edition is identical to the current German sixth edition. The proofs were read by D. Badel, E. Bauer, E. Jorg-Miiller, S. Weinfurtner, A. Jurisch and T. Wollenweber. Special thanks go to them and to Prof. U. C. Tauber and Dr. R. Hilton for comments on some of the formulations. I would like to thank all colleagues and students who have made suggestions to improve the book, as well as the publisher. Munich, January 2002 F. Schwabl Preface to the First Edition This is a textbook on quantum mechanics. In an introductory chapter, the basic postulates are established, beginning with the historical development, by the analysis of an interference experiment. From then on the organization is purely deductive. In addition to the basic ideas and numerous applica­ tions, new aspects of quantum mechanics and their experimental tests are presented. In the text, emphasis is placed on a concise, yet self-contained, presentation. The comprehensibility is guaranteed by giving all mathemati­ cal steps and by carrying out the intermediate calculations completely and thoroughly.