Physics of Massive Neutrinos

I summarize the present status of global analyses of neutrino oscillations, including the most recent KamLAND and K2K data, as well as the latest solar and atmospheric neutrino fluxes. I give the allowed ranges of the three-flavour oscillation parameters from the current worlds' global neutrino data sample, their best fit values and discuss the small parameters α≡ΔmSOL2/ΔmATM2 and sin2θ13, which characterize the strength of CP violation in neutrino oscillations. I briefly discuss neutrinoless double beta decay and the LSND neutrino oscillation hint, as well as the robustness of the neutrino oscillation results in the presence of non-standard physics.