International audienceIn this chapter are recalled the multi-secular effects of proximity constraint, or more generally accessibility, on the organization and evolution of systems of cities. The central argument is that the historical modalities of the spatial interaction between the cities constitute the major explanation of their current configurations, their organization in networks and the regularities observed over time in their dynamics, as well as their common and relatively predictable evolution. The interactions, which are generating this dynamic of cities, lead to a growing interdependence of their future. It is also through their interactions that archaeologists, historians and geographers contribute to consolidate knowledge for ...