In preparing this book, we have set ourselves the goal of presenting a unified picture of the physics of neutrinos as it now emerges from studies of nuclear physics, particle physics, astrophysics, and cosmology. While describing all aspects of neutrino physics, we focus strongly on what we know and hope to learn about the neutrino's mass and particle-antiparticle symmetry, as we consider these to be among the most burning questions.

As our readers we have in mind students in nuclear and particle physics at graduate level as well as researchers in these fields. The book thus may serve as a text in a specialized course, or as a supplement to a standard text in nuclear or particle physics. We have written each chapter sufficiently selfcontained that it can be read independently. To keep the length of the text within limits, we have provided each chapter with references to specialized review articles. Also, for the same reason, we have elected only to touch upon several topics that are not directly related to the problem of neutrino mass and mixing, such as neutral current interactions of neutrinos, electron neutrino scattering, and deep inelastic neutrino nucleon scattering.

Throughout, we have attempted to stress physical concepts, treating theoretical developments and experimental techniques on an equal footing, while including material up to Fall 1986. The prospect of finding massive neutrinos and its repercussions on our fundamental understanding of particles is exciting, as is the ingenuity of the experimental approaches in exploring neutrino mass.

We are grateful to Peter Rosen and Garry Steigman for reading the manuscript and for offering useful suggestions.