Marc Barthelemy is a senior researcher at the Institute of Theoretical Physics in Saclay (CEA) and a member of the Center of Social Analysis and Mathematics (EHESS). He has worked on applications of statistical physics to complex networks, epidemiology, and more recently, spatial networks, and is the co-author, with Alain Barrat and Alessandro Vespignani, of Dynamical Processes on Complex Networks (2008). Focusing on both data analysis and modeling, he is currently working on various aspects of the emerging science of cities.