Superfluidity and Superconductivity, Third Edition introduces the low-temperature phenomena of superfluidity and superconductivity from a unified viewpoint. The book stresses the existence of a macroscopic wave function as a central principle, presents an extensive discussion of macroscopic theories, and includes full descriptions of relevant experimental results throughout. This edition also features an additional chapter on high-temperature superconductors. With problems at the end of most chapters as well as the careful elaboration of basic principles, this comprehensive survey of experiment and theory provides an accessible and invaluable foundation for graduate students studying low-temperature physics as well as senior undergraduates taking specialized courses.