2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/48520This is a brief presentation of historical introduction to the theoretical concept of neutrino oscillation during the early stage up to 60's. (Openig address at the Europhysics NEUTRINO OSCILLATION WORKSHOP (NOW' 98), 7-9 Sept. 1998, Amsterdam.11pages, LatexHigh Energy Physics - Phenomenologytext