  Theoretical aspects of neutrino physics are reviewed, with emphasis on
possible explanations of the smallness of neutrino masses and of the peculiar
mixing pattern observed in the lepton sector. Some theoretically motivated
frameworks, such as those based on spontaneously broken discrete flavour
symmetries, are discussed, stressing the importance of low-energy observables,
like anomalous magnetic moments, electric dipole moments and lepton flavour
violating transitions, to test further features of these models.
