Why do countries trade? What goods do countries trade? What are the implications of openness for the location of production, industries, occupations, and innovative activity? And, what impedes trade and why do some countries deliberately erect policy impediments to trade? The course also concerns normative issues, such as: Is trade openness beneficial to a representative agent? And, are there winners and losers from trade and if so, can we identify them? Throughout, these issues are approached in neoclassical settings as well as those with market failures, at the industry-level as well as the firm-level, and in the presence of both mobile and immobile factors (e.g., FDI, offshoring of tasks, multinational firms and immigration).