2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/42592We review theoretical ideas, problems and implications of neutrino masses and mixing angles. We give a general discussion of schemes with three light neutrinos. Several specific examples are analyzed in some detail, particularly those that can be embedded into grand unified theories.Proceedings of the X International Workshop on "Neutrino Telescopes", March 11-14 2003, Venezia, Italy, 41 pages, 5 figuresHigh Energy Physics - Phenomenologytext