Designed for a one-year graduate course, this text provides the student with a thorough working knowledge of quantum mechanics. The book formulates quantum mechanics in terms of transformation theory, which permits the student to go immediately to the representation best suited to the particular problem at hand. Among the many outstanding features are an unusually complete treatment of scattering, including inelastic scattering; extensive use of the occupation number representation; modern and thorough coverage of perturbation theory; detailed discussion of symmetry operations; an up-to-date description of the meaning of identical particles; and a comprehensive treatment of angular momentum. The scope of the book is that of nonrelativistic quantum mechanics. Many applications are discussed in detail.