In these essays, I examine quantitatively some of the classic questions in the field of International Economics: What is the impact of international trade on consumption and productivity? How does international trade affect income inequality? How do exchange rates movements affect real output and productivity? This dissertation is composed of three chapters, each covering one of these topics.The first chapter, based on my paper "Measured Gains from International Trade" with Ariel Burstein, revisits the measurement of welfare gains from trade liberalizations. Economists so far have measured these gains using one of two alternative approaches. A first approach uses structural models to infer unobservable welfare gains from changes in trade ...