Experiments on lepton and baryon stability and oscillation phenomena

The various experiments on lepton number conservation and on nucleon stability currently being done or prepared are reviewed, and their relative merits compared and discussed. The first part of the paper is devoted to the measurement of the neutrino mass and to the present limits on the conservation of the total lepton number and of the various lepton flavours. The existing results and future projects on the strictly connected problems of neutrino oscillations at nuclear reactors, pion factories and high energy accelerators will be also discussed, together with oscillations of solar and atmospheric neutrinos. The second part of the paper concerns the few results and the many planned detectors on nucleon decay with particular emphasis on the problems of background radioactivity and of the variety of experimental approaches. Oscillation experiments on neutron-antineutron oscillations at nuclear reactors are also considered. (author)