This conference celebrated the discovery of neutral currents in neutrino interactions twenty years ago. History will mark the 1973 decisive experiments as the turning point of a new era in theoretical and experimental physics. The participants in the discovery retrace its circumstances and genesis, and all the present aspects of its heritage are reviewed: particle physics (the standard model has to date not been invalidated by the most precise experiments at LEP), atomic physics and astrophysics.

The Cargese Summer Institute 1975 on Weak and EZeotromagnetio Interaotions at High Energies was organized by the Universite Pierre et Marie Curie (M. LEVY et J.L. BASDEVANT)~ the KathoZieke Universiteit te Leuven (R. GASTMANS) and the Universite CathoZique de Louvain (D. SPEISER~ J. WEYERS) who made in 1973 the first oon taots with some Zeoturers~ who~ on the advioe of NATO joined their efforts and worked in oommon. It was the 16th Summer Institute rd heZd at Cargese and the 3 one organized by the two departments of TheoreticaZ Physios at Leuven and Louvain-Za-Neuve. When the two groups decided (independentZy) on the subjeot of the sohooZ~ they oouZd not know how Zuoky their ohoioe eventuaZZy wouZd turn out to be : rareZy has it being possibZe to present an audienoe with suoh a great number of new and deoisive disooveries who are Zikely to stimuZate the imagination of theoreticians and the researoh projeots of experimentaZists aZike. Suoh were the decisive oonfirmation of the neutraZ ourrents~ the di-muon events~ the sZowZy deoaying new partioZes~ eto. The organizers were grate JUZ indeed that they oouZd find physioists from aZmost alZ great oenters of high energy physios Who had themseZves participated in these disooveries. AZthough the theorists oouZd not matoh during the Zast two years the speotaouZar suooess of their experimentaZ ooZZeagues~ there has been enough important program~ especiaZZy in fieZd theory : renormaZization of gauge theories~ the mechanism disoovered by R. BROUT et aZ. ~ eto.

The International Conference on the History of Original Ideas and Basic Discoveries, held at the "Ettore Majorana" Centre for Scientific Culture in Erice, Sicily, July 27-August 4, 1994, brought together sixty of the leading scientists including many Nobel Laureates in high energy physics, principal contributors in other fields of physics such as high Tc superconductivity, particle accelerators and detector instrumentation, and thirty-six talented younger physicists selected from candidates throughout the world. The scientific program, including 49 lectures and a discussion session on the "Status and Future Directions in High Energy Physics" was inspired by the conference theme: The key experimental discoveries and theoretical breakthroughs of the last 50 years, in particle physics and related fields, have led us to a powerful description of matter in terms of three quark and three lepton families and four fundamental interactions. The most recent generation of experiments at e+e- and proton-proton colliders, and corresponding advances in theoretical calculations, have given us remarkably precise determinations of the basic parameters of the electroweak and strong interactions. These developments, while showing the striking internal consistency of the Standard Model, have also sharpened our view of the many unanswered questions which remain for the next generation: the origin and pattern of particle masses and families, the unification of the interactions including gravity, and the relation between the laws of physics and the initial conditions of the universe.

This volume contains a portion of the presentations given at the session on High Energy Physics and Astro physics of Orbis Scientiae II, held at the Center for Theoretical Studies, University of Miami, from January 20 through January 24, 1975. This, second in the new series of meetings held at the CTS, strove to implement the goals professed in the organization of Orbis Scientiae in 1974, namely to encourage scientists in several disciplines to exchange views, not only with colleagues who share similar research interests, but also to acquaint scientists in other fields with the leading ideas and current results in each area repre sented. Thus, an effort has been made to include papers in each session that discuss fundamental issues in a way which is comprehensible to scientists who are specialists in other areas. Also in keeping with the philosophy of Orbis Scientiae, the major topics each year are to be varied, with the invariant being the inclusion of developments in fundamental physics. The discussions of the current state of the art in high energy physics represented in this volume include new theories and experiments in the field. v PREFACE Special gratitude is due to the following for their contributions as organizers and moderators of the ses sions on high energy physics and astrophysics: Abdus Salam, Jogesh Pati, Karl Strauch, O. W. Greenberg, Sheldon Glashow, George Sudarshan and W. John Cocke. The editors wish to express their appreciation to Mrs. Helga Billings and Mrs.