"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...

Three of the most important recent facts in global macroeconomics -- the sustained rise in the US current account deficit, the stubborn decline in long run real rates, and the rise in the share of US assets in global portfolio -- appear as anomalies from the perspective of conventional wisdom...