  Current theoretical and experimental issues are reviewed in the light of the
recent SuperKamiokande discovery. By using quark-lepton symmetries, derived
from Grand Unification and/or string theories, we show how to determine the
necessary neutrino parameters. In addition, the seesaw neutrino masses set the
scale for the proton decay operators by ``measuring'' the standard model
cut-off. The SuperKamiokande values suggest that proton decay is likely to be
observed early in the XXIst Century.
