Thoroughly revised and updated, this new edition presents a coherent and comprehensive overview of modern neutrino physics. The book covers all the major areas of current interest, with chapters discussing the intrinsic properties of neutrinos, the theory of the interaction of neutrinos with matter, experimental investigations of the weak interaction in neutrino processes, the theory and supporting experiment for the basic properties of the interaction of neutrinos with fermions, and on astrophysics and cosmology. Several chapters have been completely rewritten. This edition presents new data on solar neutrinos and an update of the results of searches for double beta decay. It also contains a new chapter on direct measurements of the neutrino mass, with high precision data from experiments at Fermilab and CERN, and at the Kamiokande Laboratory in Japan. An essential reference text for particle physicists, nuclear physicists and astrophysicists.