  The observed flavor oscillations of solar and atmospheric neutrinos determine
several elements of the leptonic mixing matrix, but leave open the small mixing
angle Theta_13, a possible CP-violating phase, the mass ordering, the absolute
mass scale m_nu, and the Dirac vs. Majorana property. Progress will be made by
long-baseline, tritium endpoint, and 2-beta decay experiments. The best
constraint on m_nu obtains from cosmological precision observables, implying
that neutrinos contribute very little to the dark matter. However, massive
Majorana neutrinos may well be responsible for ordinary matter by virtue of the
leptogenesis mechanism for creating the baryon asymmetry of the universe. In
future, neutrinos could play an important role as astrophysical messengers if
point sources are discovered in high-energy neutrino telescopes. In the
low-energy range, a high-statistics observation of a galactic supernova would
allow one to observe directly the dynamics of stellar collapse and perhaps to
discriminate between certain mixing scenarios. An observation of the relic
neutrinos from all past supernovae has come within reach.
