The Solar Neutrino Problem

The solar neutrino problem has persisted for almost three decades.Recent results from Kamiokande, SAGE, and GALLEX indicate a pattern of neutrino fluxes that is very difficult to reconcile with plausible variations in standard solar models. This situation is reviewed, and suggested particle physics solutions are discussed. A summary is given of the important physics expected from SNO, Super Kamiokande, and other future experiments.