Quantum mechanics, the theoretical framework that describes microscopic physical phenomena, is a marvelous intellectual enterprise. Elegant, intriguing, challenging, often counter-intuitive and sprinkled with delightful surprises, it is wholly unlike classical physics. Mastery of quantum theory is an essential ingredient in the education of physicists and chemists. This text, a broad and deep introduction to the theory, is intended not only to help provide that mastery but also to convey to the reader its inherent richness.

The book is designed for use in year-long undergraduate courses, for self-study, and as a supplemental text in graduate courses. Its aims are achieved through a combination of introductory material, including a survey of relevant mathematics; an axiomatic formulation of the theory via six postulates; applications to soluble one-, two-, and three-dimensional systems; theoretical augmentations such as symmetry properties, electro-magnetic interactions, spin ½ and generalized angular momentum; and discussion of approximation methods and their application to electromagnetic transitions and systems of identical fermions (atoms and molecules). The reader is assumed to be familiar with material covered in courses on intermediate mechanics, electromagnetism and elementary modern physics, plus mathematics through vector calculus, elements of partial differential equations (their form and separation-of-variables solutions), and some linear algebra (finite dimensions, matrices).

The writing of this book has been strongly influenced by the author's experiences teaching both the graduate and the undergraduate quantum-theory courses at Brown University. Most of the students who take the undergraduate course are junior-level physics majors, many of whom go on to graduate school in physics.