A student's first course on quantum mechanics provides the foundation essential for much of his or her future work in physics, be it in atomic, elementary particle, or solid state physics. This introductory textbook contains not only the foundations and many applications of quantum mechanics, but also new aspects and their experimental verification. It has as its particular virtues clarity and conciseness of presentation, while at the same time being self-contained. Comprehensibility is further guaranteed by the inclusion of all the mathematical steps required for a complete understanding. Carefully chosen problems help to consolidate the student's knowledge. In the introductory chapters, starting from the historical evolution of the subject, the fundamental postulates are developed inductively by means of an interference experiment. Thereafter the structure is purely deductive, covering all of nonrelativistic quantum mechanics, plus the quantization of the radiation field in the context of optical transitions. As well as the quantum mechanical "essentials", for instance, detailed treatments of scattering theory, time dependent phenomena, and the density matrix, such topics as the theory of quantum mechanical measurement and the Bell inequality are dis- cussed. A separate chapter is devoted to supersymmetric quantum mechanics, an area which to date has been accessible only in the research literature.