"Any reader with a background in quantum mechanics and statistical physics will find the book accessible. . . . The writing style is fresh and lively." Robert B. Hallock, University of Massachusetts This edition of a classic of modern theoretical physics is a corrected reprint of the original 1990 publication. It remains the only self-contained and comprehensive monograph on the superfluid phases of Helium 3. Not only is superfluid Helium 3 one of the most fascinating of all condensed matter systems but it has also helped to shape and to test many important new ideas in modern theoretical physics.The self-contained treatment begins with a thorough but elementary discussion of the properties of superfluid Helium 3 and related fundamental ideas. The authors subsequently develop the concepts and results of the theory in all its aspects. Experienced researchers and graduate students alike will find this unique volume valuable and stimulating, whether working in this field or applying these concepts and methods to other systems. Supplements include an extensive reference list containing more than 1,300 entries and a new Preface in which the authors discuss the most important developments in this field during the last two decades. "Will automatically become the standard text on superfluid helium-3. Given its thoroughness, wide coverage, and excellent quality, it also appears very likely to maintain this position for many years into the future." P. V. E. McClintock, Lancaster University Corrected, unabridged reprint of the Taylor & Francis, London, 1990 edition.