This chapter surveys recent developments in agglomeration theory within a unifying framework. We highlight how locational fundamentals, agglomeration economies, the spatial sorting of heterogeneous agents, and selection effects affect the size, productivity, composition, and inequality of...

Equilibria and optima generally differ in imperfectly competitive markets. While this is well understood theoretically, it is unclear how large the welfare distortions are in the aggregate economy. Do they matter quantitatively? To answer this question, we develop a multi-sector monopolistic...

Quantitative spatial economics (QSE) specifies various components such as preferences, production technology, and frictions for the movement of goods, people, and ideas. Despite the long literature on endogenous location decisions, the question of how these specifications affect resulting...