Kostas Papaioannou (Volos 1925 - Paris 1981) took part in the Greek Resistance, and collaborated with the magazine Σοσιαλιστική Επιθεώρηση. He was forced to leave Greece in 1945 and to emigrate to Paris, where he became a student of R. Aron. He built his academical career as attache de recherche in CNRS since 1963 and as charge de cours in Sociology and Philosophy, mainly in Ecole Pratique (since 1971).