This new and creatively conceived casebook introduces the international legal order as it presents itself at the beginning of the twenty-first century. Consistently and effectively blending theory and practice, it is designed to give students the basic knowledge and understanding of transnational law that every modern lawyer should possess. This is an ideal text both for students who will take only one course in international law, and for those seeking a solid foundation for more specialized courses. It is organized around five major themes: actors, interactions among actors, substantive norms, methods of dispute resolution, and domestic effects of transnational law. Students are first shown how classical international law emerged and, most important, how it has evolved into modern transnational law. They are then invited to revisit each of the five core themes in the context of cutting-edge contemporary legal challenges. The casebook's unique approach enables students to gain both the knowledge and confidence they need to approach the increasingly complex range of transactions and disputes that reach beyond national boundaries.