  In this review we present the main features of the current status of neutrino
physics. After a review of the theory of neutrino mixing and oscillations, we
discuss the current status of solar and atmospheric neutrino oscillation
experiments. We show that the current data can be nicely accommodated in the
framework of three-neutrino mixing. We discuss also the problem of the
determination of the absolute neutrino mass scale through Tritium beta-decay
experiments and astrophysical observations, and the exploration of the Majorana
nature of massive neutrinos through neutrinoless double-beta decay experiments.
Finally, future prospects are briefly discussed.
