In the new edition supplements have been added at various places, includ- ing the formulation of some of the problems. In all these additions I have attempted not to change the compact character of the book. The present (second) English edition is, besides the problems and smaller corrections, identical to the current German fourth edition. The proofs were read by B. Kaufmann, M. Hummel and A. Vilfan. I would like to thank all colleagues and students who made suggestions to improve the book as well as the pub- lisher. Special thanks go to S. Clar for preparing the new ‘JEX file. Munich, March 1995 F. Schwabl Preface to the First Edition This is a textbook on quantum mechanics. In an introductory chapter, the ba- sic 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 applications, new aspects of quantum mechanics and their experimental tests are pre- sented. In the text, emphasis is placed on a concise, yet self-contained, presen- tation. The comprehensibility is guaranteed by giving all mathematical steps and by carrying out the intermediate calculations completely and thoroughly.