The division of labor between and within countries is driven by two fundamental forces, comparative advantage and increasing returns. We set up a simple Ricardian model with a Marshallian input sharing mechanism to study their interplay. The key insight that emerges is that the interaction...

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...

Being a "jack-of-all-trades" increases the probability of running an entrepreneurial venture successfully; but what happens to "jack-of-few-trades" who lack sufficient skills? This paper investigates a possible compensation mechanism between balanced skills and cities, and how this compensatory...