Thomas Faist develops a new and very interesting analysis about international migrations: as class struggle parameters at national level are no more accurate to understand migration at global level, he suggests and develops that inequalities at world level are the most pertinent factors explaining migration flows, namely social insecurity in countries of origin. The transnational social question becomes so the key factor. He ends his book by the difficult dialogue between scientists and political decision makers on migrations, coming back to the Weberian paradigm.