The 1990 Cargese Summer Institute on ZO-Physics was organized by the Univer- site Pierre et Marie Curie, Paris (M. Levy and J.-L. Basdevant), CERN (M. Jacob), the Universite Catholique de Louvain (D. Speiser and J. Weyers), and the Katholieke Universiteit te Leuven (R. Gastmans), which, since 1975, have joined their efforts and worked in common. It was the ninth Summer Institute on High Energy Physics orga- nized jointly at Cargese by these three universities. Because of the start-up of LEP in the summer of 1989, we broke with our tradition of having our Summer Institutes in the odd years. Indeed, it seemed to us that the many new data from LEP had to be presented in detail as soon as possible in order to prepare the young researchers in particle physics better for the experimental results with which they will be confronted in the coming years. The main theme of the school was therefore ZO-physics, with particular emphasis on the way the experiments at LEP are analyzed. We had one lecturer from each LEP experiment: they agreed among each other to present different topics in e+e- physics. Nevertheless, they made sure that all the major topics were discussed and that the results could be critically compared.

Paul Adrien Maurice Dirac was one of the founders of quantum theory. He is numbered alongside Newton, Maxwell and Einstein as one of the greatest physicists of all time. Together the lectures in this volume, originally presented on the occasion of the dedication ceremony for a plaque honoring Dirac in Westminster Abbey, give a unique insight into the relationship between Dirac's character and his scientific achievements. The text begins with the dedication address given by Stephen Hawking at the ceremony. Then Abraham Pais describes Dirac as a person and his approach to his work. Maurice Jacob explains how Dirac was led to introduce the concept of antimatter, and its central role in modern particle physics and cosmology. This is followed by David Olive's account of the origin and enduring influence of Dirac's work on magnetic monopoles. Finally, Sir Michael Atiyah explains the deep and widespread significance of the Dirac equation in mathematics.

The 1990 Cargese Summer Institute on ZO-Physics was organized by the Univer- site Pierre et Marie Curie, Paris (M. Levy and J.-L. Basdevant), CERN (M. Jacob), the Universite Catholique de Louvain (D. Speiser and J. Weyers), and the Katholieke Universiteit te Leuven (R. Gastmans), which, since 1975, have joined their efforts and worked in common. It was the ninth Summer Institute on High Energy Physics orga- nized jointly at Cargese by these three universities. Because of the start-up of LEP in the summer of 1989, we broke with our tradition of having our Summer Institutes in the odd years. Indeed, it seemed to us that the many new data from LEP had to be presented in detail as soon as possible in order to prepare the young researchers in particle physics better for the experimental results with which they will be confronted in the coming years. The main theme of the school was therefore ZO-physics, with particular emphasis on the way the experiments at LEP are analyzed. We had one lecturer from each LEP experiment: they agreed among each other to present different topics in e+e- physics. Nevertheless, they made sure that all the major topics were discussed and that the results could be critically compared.

The 1981 Cargese Summer Institute on Fundamental Interactions was organized by the Universite Pierre et Marie Curie, Paris (M. LEVY and J-L. BASDEVANT), CERN (M. JACOB), the Universite Catholique de Louvain (D. SPEISER and J. WEYERS), and the Kotholieke Universiteit te Leuven (R. GASTMANS), which, since 1975 have joined their efforts and worked in common. It was the 24th Summer Institute held at Cargese and the 8th one organized by the two institutes of theoretical physics at Leuven and Louvain-Ia-Neuve. The 1985 school was centered around two main themes : the standard model of the fundamental interactions (and beyond) and astrophysics. The remarkable advances in the theoretical understanding and experimental confirmation of the standard model were reviewed in several lectures where the reader will find a thorough analysis of recent experiments as well as a detailed comparaison of the standard model with experiment. On a more theoretical side, supersymmetry, supergravity and strings were discussed as well. The second theme concerns astrophysics where the school was quite successful in bridging the gap between this fascinating subject and more conventional particle physics. We owe many thanks to all those who have made this Summer Institute possible ! Thanks are due to the Scientific Committee of NATO and its President and to the "Region Corse" for a generous grant. .. We wish to thank Miss M-F. HANSELER, Mrs ALRIFRAI, Mr and Mrs ARIANO, and Mr BERNIA and all others from Paris, Leuven, Louvain-la-Neuve and especially Cargese for their collaboration.

The 1979 Cargese Summer Institute on Quarks and Leptons was organized by the Universite Pierre et Marie Curie, Paris (M. LEVY and J.-L. BASDEVANT), CERN (M. JACOB), the Universite Catholi~ue de Louvain (D. SPEISER and J. WEYERS), and the Katholieke Universiteit te Leuven (R. GASTMANS), who, like in 1975 and 1977, had joined their efforts and worked in common. It was the 20th Summer Institute held at Cargese and the 5th one organized by the two institutes of theoretical physics at Leuven and Louvain-la- Neuve. This time, the school was dominated by the impressive advances which were made in the field of perturbative ~uantum chromodyna- mics and its applications to high energy phenomena involving strongly interacting particles. The unification of weak and electromagnetic interactions being well established, a new picture in particle physics emerges wherein a possible unification of weak, electromagnetic, and strong forces is put forward. Its conse~uences were also discussed in detail. Finally, to complete the picture of the present status of high energy physics, experi- mentalists from the major laboratories around the world reported on the latest developments in electron-positron scattering, neutrino induced reactions, and hadron collisions. We owe many thanks to all those who have made this Summer Institute possible! Thanks are due to the Scientific Committee of NATO and its President for a generous grant and especially to the head of the Scientific Affairs Division, Dr. M. DI LULLO for his constant help and encouragements.

The 1983 Cargese Summer Institute on Particles and Fields was organized by the Universite Pierre et Marie Curie, Paris (M. LEVY and J.-L. BASDEVANT), C.E.R.N. (M. JACOB), the Universite Catholique de Louvain (D. SPEISER and J. WEYERS), and the Katholieke Universiteit Leuven (R. GASTMANS). After 1975, 1977, 1979, and 1981, it was the fifth time they joined their efforts for organizing this Summer Insti- tute. This school was characterized by simultaneous progress in the theory of elementary particles and by impressive experimental advances. On the theoretical front, one witnessed the new developments in lattice gauge theories, which explore the world of strongly interacting par- ticles in a non-perturbative way, and progress in a better understan- ding of the unity of all interactions based on supersymmetry. The experimentalists were ~roud to announce the discovery of the interme- diate vector bosons; W- and ZO, at C.E.R.N., while physicists working with e+e- colliding beams continued to probe more deeply the validity of the theoretical models of strong, weak and electromagnetic inter- actions. We owe many thanks to all those who have made this Summer Insti- tute possible! Thanks are due to the Scientific Committee of NATO and its Presi- dent for a generous grant and especially to the head of the Advanced Study Institute Program and his collaborators for their constant help and encouragement. We also thank the National Science Foundation (USA) for their financial assistance.

The 1992 Cargese Summer Institute on Quantitative Particle Physics was organized by the Universite Pierre et Marie Curie, Paris (M. Levy and J. -L. Basdevant), CERN (M. Jacob), the Ecole Normale Superieure, Paris (J. Diopoulos), the Katholieke Universiteit te Leuven (R. Gastmans) and the Universite Catholique de Louvain (J-M. Gerard), which, since 1975, have joined their efforts and worked in common. It was the tenth Summer Institute on High Energy Physics organized jointly at Cargese by these three universities. The 1992 School centered on quantitative tests of the Standard Model for electroweak and strong interactions. First, Professor T. D. Lee reviewed the fascinating history of weak interactions. Professor R. Barbieri then discussed the implications of the of LEP presented by Professor Foil. . Professor G. Ecker latest experimental results described in detail the interplay between electroweak and strong interactions at low energy. Professors K. Berkelman and J-M. Gerard stressed the necessity to study the effects of CP-violation in both B-and K-physics. The first results of the HERA machine were presented by Professor G. Wolf, while Professor M. Shochet reviewed heavy flavor physics in hadron collider experiments. Recent non-accelerator experiments in neutrino physics were presented by Professor B. Barish. Finally, Professor M. Turner reviewed Cosmology after COBE. We owe many thanks to all those who have made this Summer Institute possible! Special thanks are due to the Scientific Committee of NATO and its President for a generous grant.

The 1989 Cargese Summer Institute on Particle Physics was organized by the Universite Pierre et Marie Curie, Paris (M. Levy and J.-L. Basdevant), CERN (M. Jacob), the Universite Catholique de Louvain (D. Speiser and J. Weyers) and the Katholieke Universiteit te Leuven (R. Gastmans), which, since 1975, have joined their efforts and worked in common. It was the twenty-sixth Summer Institute held at Cargese and the tenth organized by the two Institutes of Theoretical Physics at Leuven and Louvain-la-Neuve. The 1989 school centered on the following topics - new experimental results - strings, superstrings and conformal field theory - lattice approximations. Of the many new experimental results, we would like to mention especially those from SLAC presented by Professor G. Feldman. On the other hand, we had the tantalizing knowledge that LEP would begin to operate only right after the end of the school! For this we received ample replacement: Professor J. Steinberger summed up all major CP violation experiments done to date and commented upon them. The reader will find also various other most interesting contributions, for instance on high energy ion beams. Once more theoreticians and experimentalists (this time more than usual) came together to discuss high energy particle physics.

Paul Adrien Maurice Dirac was one of the founders of quantum theory. He is numbered alongside Newton, Maxwell and Einstein as one of the greatest physicists of all time. Together the lectures in this volume, originally presented on the occasion of the dedication ceremony for a plaque commemorating Dirac in Westminster Abbey, give a unique insight into the relationship between Dirac's character and his scientific achievements. The text begins with the dedication address given by Stephen Hawking at the ceremony. Then Abraham Pais describes Dirac as a person and his approach to his work. Maurice Jacob explains how Dirac was led to introduce the concept of antimatter, and its central role in modern particle physics and cosmology, followed by an account by David Olive of the origin and enduring influence of Dirac's work on magnetic monopoles. Finally, Sir Michael Atiyah explains the deep and widespread significance of the Dirac equation in mathematics.