This introduction was originally published in French as “Mobilités, catégorisation et appartenance. Un défi de réflexivité,” Annales HSS 76, no. 3 (2021): 445–55.

We would like to thank Nora Berend, Deepra Dandekar, Marc Horton, Christoph Kalter, Friedrich Lenger, Elena Isayev, and Thomas Weller for their comments as we began to work on this transtemporal approach. We have learned a great deal from them and from their research on human mobilities in different temporal spaces, from the last two millennia in East Africa to the collapse of the Portuguese Empire in the final third of the twentieth century. We are also grateful to Eveline G. Bouwers, Jana Bruggmann, Noëmie Duhaut, Bernhard Gißibl, Denise Klein, Sarah Panter, Johannes Paulmann, and John Carter Wood at the Leibniz Institute of European History, and to the Annales editorial board for their valuable comments on earlier drafts of this text.