The 1996 Carg~se Summer Institute on Frontiers in Particle Physics was organized by the Universite Pierre et Marie Curie, Paris (M. Levy), the Ecole Nonnale SupCrieure, Paris (J. lliopoulos), the Katholieke Universiteit 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 twelfth Sunnner Institute on High Energy Physics organized jointly at Carg~se...