We illustrate the figure of the Italian mathematician Giovanni Torelli, working in Trieste from the end of the 1950s to the late 1980s, in relation to his activities in the field of mathematics education. In particular, we describe his teaching methodology in secondary school and university, his methodological motivations, his collaboration with teachers in the “Nucleo di Ricerca Didattica di Trieste” (Trieste Teaching Research Unit). Finally, some of his important initiatives in the field of secondary school teacher training are shown.
