More than half of the world's seven billion people now live in cities. Scholars in urban history study how this happened: how the process of urbanization has unfolded in different places and times, and how that process was related to economic, political, cultural, and social changes. We are also interested in the growth of particular cities, and in the interplay of race, class, religion, gender, and public policy that has shaped spatial development and the lives of individuals in particular urban contexts. Urban historians work in every geographic and temporal field, and collaborate with sociologists, economists, political scientists, and scholars of art and literature. Several department members with urban interests have affiliations with the Institute for Policy Research and the Buffett Institute.