Alongside the traditional topics of international trade theory, this useful textbook integrates many topics usually omitted, and contains results of new research. It may be used at both undergraduate and graduate level, thanks to its unique "two-tier" structure: the text speaks directly to the undergraduate in extremly clear terms, while the appendices, which form the second tier, are addressed to graduate students and researchers. Each appendix is a self-contained treatment in mathematical terms of the topics examined in the text. The ample and balanced treatment of the various approaches and the clarity of exposition ensure that readers gain a thorough grasp of theories, facts and policies.