The objective of this chapter is threefold: showing how research activity is spatially organized in the contemporary world at different scales, what are the different means and datasets available to measure its spatial distribution, and what can explain the degree of polarization of this activity. The chapter adopts a critical view on the literature that stresses the spatial polarization of this activity as if it was a necessary feature of it. First, the chapter demonstrates that contrary to most expectations, this polarization has globally diminished since the second part of the twentieth century. Second, taking the example of the regional distribution of research in Europe, it insists on the various means and sources used to study this distribution and its evolution through time. To finish, it highlights an overlooked dimension of research activity: the fact that the institutional geography (authors’ affiliations) does not reflect where research is actually done, especially in the case of field ground-based research; and it gives some direction for future research.