Thomas Friedman (2005, The World Is Flat: A Brief History of the Twenty-First Century. New York: Farrar, Straus, and Giroux) argues that the expansion of trade, the internationalization of firms, the galloping process of outsourcing and the possibility of networking are creating a lsquo;flat...

This handbook chapter studies the theoretical micro-foundations of urban agglomeration economies. We distinguish three types of micro-foundations, based on sharing, matching, and learning mechanisms. For each of these three categories, we develop one or more core models in detail and discuss the...