Keywords: Bruno Trentin; Socialism; Trade Unions; Knowledge Society; Working Class.
The article retraces the actuality of Bruno Trentin's socio-political activity, as a trade union leader, a politician, and a social theorist. Starting from Iginio Ariemma's book, "La sinistra di Bruno Trentin" ("Bruno Trentin's Left"), the author analyzes the origins of Trentin's conception of labor and his role in the Cgil Trade Union. His libertarian socialism is above all a challenge towards the sudden evolution of Italian society after World War II. In this perspective, the trade unions seem to suffer now the same risk of a separation from the social and working "avant-gardes" which Trentin envisaged in his times: now represented by the knowledge society.