Urbanization almost invariably accompanies development, and the cities of India and China are experiencing spectacular increases in population. The concentration of millions of people in a small mass creates challenges for public policy, especially in the areas of basic infrastructure, public health, traffic congestion, and often law enforcement as well. In this essay, I discuss five core debates in urban policy, including the optimal degree of federalism, private versus public provision of urban services, optimal land use regulation, appropriate spatial policies, and the use of engineering and economics approaches to reducing the negative consequences of density. None of these debates are close to being resolved, but researchers have managed to generate a number of useful insights in these areas. © 2011 by the Association for Public Policy Analysis and Management.