2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/229241In these lectures (at the 2007 Summer School in Akyaka, Mugla, Turkey), I discuss the various mechanisms for obtaining small Majorana neutrino masses, as well as specific models of varying complexity, in the context of the standard model and beyond.20 pages, 5 figuresHigh Energy Physics - Phenomenologytext