The essay deals with the theme of the «philosophy of dialogue» of Guido Calogero, conceived in the context of his intellectual development, from the beginnings in the mid-Twenties as a historian of the ancient philosophy at Giovanni Gentile’s school, to the growing up in him of an autonomous philosophical personality and, since the mid-Thirties, of a more and more tangible political engagement, built in a steady discussion with Benedetto Croce. Calogero’s «philosophy of dialogue» reveals itself as being more a moral philosophy than a political one, even as the outcome of the failure both of the liberal-socialist proposal and of the subsequent Action’s Party, in which Calogero much had invested, assuming in it important executive roles.