Historically, urban growth required enough development to grow and transport significant agricultural surpluses or a government effective enough to build an empire. But there has been an explosion of poor mega-cities over the last thirty years. A simple urban model illustrates that in closed...

The majority of labor transactions throughout much of history and a significant fraction of such transactions in many developing countries today are "coercive", in the sense that force or the threat of force plays a central role in convincing workers to accept employment or its terms. We propose...

In this paper, I develop a model to analyze how skill premia differ over time and across countries, and use this model to study the impact of international trade on wage inequality. Skill premia are determined by technology and the relative supply of skills. An increase in the relative supply of...