This thesis presents the social engineering as devised by Otto Neurath (1882-1945), an Austrian economist, sociologist, and philosopher. The introductory first part highlights certain issues of his biography which turned out significant in his subsequent idea of the necessity of a targeted and planned intervention in the social order. In part two, the technique of conceptual history reveals the mental representations at work in social engineering : the topos of "modernity" – built on a new concept of society, of time, and of the potential role of civil society – suggests the feasibility of managing a social group according to principles of rationalization of life.Neurath’s Gesellschaftstechnik is then reconstructed by the method of intellectual history, which shows the Viennese context, the dynamics involved in the 1918-19 German Revolution, and the economic concerns of the time as being essential for the development of his thought and his programme of social eudaimonism.