Theoretical interpretation of recent neutrino oscillation data

The theoretical interpretation of the current neutrino phenomenology is reviewed in the context of three and four neutrino mixing. We discuss the status of atmospheric nu-mu oscillations and the recent indications from the KEK-to-Kamioka (K2K) experiment. We also review the status of solar nu-e oscillations after the Sudbury Neutrino Observatory (SNO) measurements. The three-neutrino mixing scenario emerges as a consistent theoretical interpretation of solar, atmospheric, and reactor data. Conversely, the inclusion of LSND accelerator data in an extended four-neutrino scenario generates a "tension" between data subsets in global fits. We also comment on the role of possible new neutrino interactions.