The following proceedings contains most of the contributions given at Orbis Scientiae 1981. As has become customary during the past few years, the organizers and moderators have attempted to strike a balance between reviews of the status of experimental and theoretical developments during the preceding year. We are very pleased that experimentalists representing the critical developments in new accelerator plans, neutrino oscillations, proton decay, and decay schemes of the upsilon, have seen fit to enlighten at first hand their theoretical colleagues. We believe that this interaction can be of great benefit to both groups. The reports of theorists on many of the key theoretical advances by the practitioners themselves is a particularly satisfying feature of this series of conferences and is a tribute to the care and wisdom of the session moderators. Although it has not been a customary editorial practice, we feel that it is particularly appropriate to point out that the 1981 recipient of the J. Robert Oppenheimer Memorial Prize was Professor Frederick Reines, of University of California, Irvine, for his pioneering experiments which first experimentally estab lished the existence of the neutrino. The flurry of activit- experimental and theoretical - generated by recent evidence for massive neutrinos is amply reflected in the contents of this volume. The enthusiasm and skill of Mrs. Helga S. Billings and Mrs. Susan L. Maxon in the organization and the running of the con ference, as well as in the preparation of these proceedings, is gratefully acknowledged.

Reviews the current state of knowledge of neutrino masses and the related question of neutrino oscillations. After an overview of the theory of neutrino masses and mixings, detailed accounts are given of the laboratory limits on neutrino masses, astrophysical and cosmological constraints on those masses, experimental results on neutrino oscillations, the theoretical interpretation of those results, and theoretical models of neutrino masses and mixings. The book concludes with an examination of the potential of long-baseline experiments. This is an essential reference text for workers in elementary-particle physics, nuclear physics, and astrophysics.

This volume contains the greater part of the papers submitted to the Information Processing in Biology portion of the 1983 Orbis Scientiae, then dedicated to the eightieth year of Professor P.A.M. Dirac. Before the volume could be published, Professor Dirac passed away on October 20, 1984, thereby changing the dedica tion of this volume, and its companion, on High Energy Physics, to his everlasting memory. The last Orbis Scientiae (as it was often in the past) was shared by two frontier fields - in this case by High Energy Physics and Information Processing in Biology, demonstrating the universality of scientific principles and goals. The interaction amongst scientists of diverse interests can only enhance the fruitfulness of their efforts. The editors take pride in the modest contribution of Orbis Scientiae towards this goal. It is a pleasure to acknowledge the typing of these proceedings by Regelio Rodriguez and Helga Billings, and the customary excellent supervision by the latter. The efficient preparation and organiza tion of the conference was due largely to the skill and dedication of Linda Scott. As in the past, Orbis Scientiae 1983 received nominal support from the United States Department of Energy and the National Science Foundation.

This volume contains the greater part of the papers submitted to the High Energy Physics portion of the 1983 Orbis Scientiae, then dedicated to the eightieth year of Professor P. A. M. Dirac. Before the vol,ume could be published, Professor Dirac passed away on October 20, 1984, thereby changing the dedication of this volume, and its companion, on Information Processing in Biology, to his everlasting memory. Since 1969, Professor Dirac had given the opening address at each of these conferences. He was unable to prepare a manuscript of his last paper in 1983. His impact on science already has been enormous. The consequences of his thought and work for future developments are incalculable. Regrettably, Professor Dirac's last appearance at this series of conferences, begun in 1964 as the Coral Gables Conference on Symmetry Principles at High Energy, coincided with the twentieth, and the last of these. The work and expense involved in organizing them and preparing the proceedings have corne to far exceed the physical capabilities and the support received by the Center for Theoretical Studies for this program. The delayed appearance of these proceedings, for which the editors humbly apologize, is a manifestation of the inadequate support. On the other hand, the organizers and editors thank the many distinguished participants who, over the years, made these meetings exciting and productive arenas for the dissemination of ideas in high energy physics and related fields.

What is unorthodox in this book? Much has happened in the last few years, especially in terms of the somewhat surpris ing rate at which the theories presented herein have been gaining increasing acceptance and support even by the most skeptical professionals. Nevertheless, the purpose of this up-dated Preface is not to tell the biographical and acceptance story behind this book, but to bring together some non-physical and non technical conclusions for those readers who find the physico-mathematical sections of this book too difficult to follow. A secondary purpose is to present here some newer conclu sions, especially in general philosophy and in aesthetics. Yet, the main physico philosophical conclusions presented in this book are not to be summarized here. For that purpose one must tum to the text itself. * * * The theories presented here have been developed in total isolation. They were never presented in "professional conferences", as most current writers do. Whether or not that was important remains to be seen. Hence, all I can state to critics and enthusiastic follow ers alike is the fact that I do not belong to any 'formal discipline', 'pressure group', or 'pro fessional organization'.

Editors Laurie Brown, Max Dresden, Lillian Hoddeson and Michael Riordan have brought together a distinguished group of elementary particle physicists and historians of science to explore the recent history of particle physics. Based on a conference held at Stanford University, this is the third volume of a series recounting the history of particle physics and offers the most up-to-date account of the rise of the Standard Model, which explains the microstructure of the world in terms of quarks and leptons and their interactions. Major contributors include Steven Weinberg, Murray Gell-Mann, Michael Redhead, Silvan Schweber, Leon Lederman and John Heilbron. The wide-ranging articles explore the detailed scientific experiments, the institutional settings in which they took place, and the ways in which the many details of the puzzle fit together to account for the Standard Model.

The first full length biography of Dirac, one of the most brilliant physicists of the twentieth century.