Maybe the Landless Workers' Movement (MST) of Brazil has one of the hugest social base and most radical leftist program in Latin America. It constitutes an unavoidable reference for all contemporary leftist peasant movements both in Latin America and in the other continents as well. Its legendary combative land occupations and its highly organized and conscious autonomist system of popular education in the spirit of Paulo Freire designate the MST to be the most massive and theoretically most advanced bloc of the Via Campesina. The author, a Brazilian sociologist, presents us a relatively detailed account of the main practices of the movement, of its theoretical starting points and also its practical results.