Since cities are likely to play an even more predominant role in the global economy in the future than they do at present, it is important to understand how urban centers are created, grow, and function in the process of generating and distributing wealth. This integrated collection of essays exploring the new economic theory of cities assembles recent work by a number of the world's leading exponents in North America, the UK/Europe, and Japan. Topics investigated include cities and agglomeration, urban systems, urbanization and growth, and cities and factor markets. The perspectives the editors and contributors offer have strong connections with several branches of modern economics, including industrial organization, public economics, international trade, and endogenous growth and economic development.