We study the relationship between geography and growth. To do so, we first develop a dynamic spatial growth theory with realistic geography. We characterize the model and its balanced growth path and propose a methodology to analyze equilibria with different levels of migration frictions. We...

We present a theory of spatial development. A continuum of locations in a geographic area choose each period how much to innovate (if at all) in manufacturing and services. Locations can trade subject to transport costs and technology diffuses spatially across locations. The result is an...

This paper studies the recent spatial development of India. Services, and to a lesser extent manufacturing, are increasingly concentrating in high-density clusters. This stands in contrast with the United States, where in the last decades services have tended to grow fastest in medium-density...

"Examines trend toward digital means of consumer payments, asking several questions: How will digital money evolve? What impacts will technologies such as wireless devices have on payment for goods and services? What other technologies await consumers? And what will the consumer payments...

This paper proposes a simple theory of a system of cities that decomposes the determinants of the city size distribution into three main components: efficiency, amenities, and frictions. Higher efficiency and better amenities lead to larger cities, but also to greater frictions through...