The world economy has entered a dangerous period. Some of the financial turmoil in Europe has spread to developing and other high-income countries, which until earlier had been unaffected. This contagion has pushed up borrowing costs in many parts of the world, and pushed down stock markets,...

Economic theory, including endogenous growth, the role of institutions, and, most importantly, the New Economic Geography (NEG), have made significant progress in explaining the emergence of core-periphery patterns behind this divergence. They point to the critical role of agglomeration, which...