The physics of neutrinos has acquired a rapidly increasing role within the realm of particle physics. Recognized as an elusive particle since the prediction of its existence by Pauli and its incorporation into particle theory by Fermi in the early thirties, the neutrino was first observed some twenty years later by Reines and Cowan. Experiments carried out by Lederman, Schwartz, Steinberger et al. first revealed the existence of several species of neutrinos. By now, neutrino physics has matured to the point where detailed properties of neutrinos and their mixing can be studied by a number of...

The twentieth Johns Hopkins Workshop on current problems in particle theory took place in Heidelberg. The topic of the workshop was chosen in view of the phantastic success enjoyed by the standard model of electroweak and strong interactions.Until today, no significant deviations from the predictions of the standard model have been observed. However, precision tests have been dominantly performed in the high-energy domain, where the QCD coupling constant is small enough to allow for a perturbative treatment of the strong interaction. It is therefore very important to consider also the...

The workshop collected together theoreticians and experimentalists for a discussion about the most recent experiments and their impact on theoretical ideas. The discussion included the new data from LEP and SLD, the evidence for the top quark from Tevatron, the structure function measurements from HERA, and the searches for dark matter. Also, new projects for physics with large neutrino detectors and CP violation at e+e- factories were presented, and a survey of high energy astroparticle physics was included. Particular attention was paid to the interplay between microscopical and...