This edition differs from the second chiefly in the addition of about 100 pages devoted to the quantum (or geometric, or Berry) phase, a subject that did not exist when this book was written. The changes in the remainder of the book consist of corrections of a small number of misprints. While it may seem that adding two chapters on the quantum phase is overemphasizing a currently fashionable subject, they actually complete the development of quantum theory as given in this book. We start with simple models, synthesizing them into complicated "molecules." With the new chap ters. we end with complicated "molecules," dividing them into simpler parts. This process of dividing a complex system into parts quite naturally gives rise to a gauge theory, of which the geometric phase is a manifestation - with consequences not only in theory, but observable in experiments. For this rea son, the geometric phase is not a mere fashion, but a discovery that will retain its importance forever and must be discussed in textbooks on quantum mechanics. to acknowledge help and advice from Mark Loewe with the I would like writing and also of the new part of the book. In addition, I would like to express my gratitude to J. Anandan, M. Berry, and c.A. Mead, who have read parts or all of the new material and have provided valuable advice.

Inhalt
I Mathematical Preliminaries.- II Foundations of Quantum MechanicsThe Harmonic Oscillator.- III Energy Spectra of Some Molecules.- IV Complete Systems of Commuting Observables.- V Addition of Angular MomentaThe Wigner-Eckart Theorem.- VI Hydrogen AtomThe Quantum-Mechanical Kepler Problem.- VII Alkali Atoms and the Schrödinger Equation of One-Electron Atoms.- VIII Perturbation Theory.- IX Electron Spin.- X Indistinguishable Particles.- XI Two-Electron SystemsThe Helium Atom.- XII Time Evolution.- XIII Some Fundamental Properties of Quantum Mechanics.- XIV Transitions in Quantum Physical SystemsCross Section.- XV Formal Scattering Theory and Other Theoretical Considerations.- XVI Elastic and Inelastic Scattering for Spherically Symmetric Interactions.- XVII Free and Exact Radial Wave Functions.- XVIII Resonance Phenomena.- XIX Time Reversal.- XX Resonances in Multichannel Systems.- XXI The Decay of Unstable Physical Systems.- XXII Quantal Phase Factors and Their Consequences.- XXIIIA Quantum Physical System in a Quantum EnvironmentThe Gauge Theory of Molecular Physics.- Epilogue.