[en] This survey of experiment and theory, supplemented by problems at the end of most chapters, is an invaluable foundation text for graduate students in the field. The text is the first to introduce the low-temperature phenomena of superfluidity and superconductivity from a coherent viewpoint, with the existence of a macroscopic wavefunction stressed as the central principle. Extensive discussion covers macroscopic theories, with major chapters on condensates and excitations, the two-fluid model, vortex states and Josephson effects. The main development in the field of superfluid physics since the first edition has been the confirmation of superfluidity in the A and B phases of liquid ³He, which is here described in terms of a microscopic theory of pairing of ³He atoms. An introduction to the Ginzburg-Landau theory is also given. In order to prepare the reader for the microscopic treatment, and in recognition of its importance to the subject, the authors have expanded their earlier treatment of the Bardeen-Cooper-Schrieffer theory of superconductors to a full chapter