This textbook on quantum mechanics has been designed for use in two-semester undergraduate courses. It describes the basic concepts of quantum mechanics, explains the use of the mathematical formalism and provides illustrative examples of both concepts and methods. Although the aim is to enable students to master the use of quantum mechanics as a tool, the author also discusses the meaning of quantum concepts. To this end the book contains a variety of relevant examples, worked out in considerable detail, as well as a substantial number of pertinent problems and exercises. The latter will be extremely helpful, if not essential, for gaining a deep understanding and command of the subject. This book is based on the author's thirty years experience of teaching the subject.