The course intends to help the student think about four aspects of international trade - Static and dynamic welfare effects of trade and their distribution, - Direction and type of goods and service flows accross countries, - Market imperfections and asymmetries, - Strategies of firms and governments in imperfectly competitive markets. It is hoped that the students become flexible enough to discuss the above issues from the viewpoint of aggregate economic efficiency and equity as well as this specific agents'interests, like the firm or one of its components (labor, shareholders, managers, regulators, customers, ...). A certain insight into the art of modeling, or at least of formalizing arguments is also presented.