The 5th international conference spotlighted the concept of population as a central issue in the debates within territorial sciences. Central to demography and biology and more marginal for other disciplines, it involves the grouping together of individual entities. Linking together population, time and territory in a transdisciplinary and international perspective was the main goal of this conference; beyond the fact that it represented a theoretical and methodological breakthrough, the diversity of the proposed thematic sessions was a clear sign that this trio is at the heart of contemporary issues.