The aim of this dissertation is to study critical urban geography through three contemporary groups which claim to partake in it : Brazil’s GESP (Grupo de Estudos sobre São Paulo), Germany’s Kritische Geographie Berlin, and the international network of INURA (International Network for Urban Research and Action). This method is inspired by the science studies and implies studying what is being done just as much as whatever theoretical content is being produced. In this view, ideas exist only insofar as they are borne, carried out and broadcast by these groups. From the data collected, it is possible, by crosschecking, to define critical urban geography as « on the threshold » : between the normative and the descriptive, between theory and practice, at the margins of the academic and scientific fields. This research also purports to assess whether the bonds between these groups are strong enough to allow us to talk about a global current of thought.