This seminar uses the methods of law and economics to examine alternative sources of law and to provide some insights on the institutional theory of lawmaking. Part 1 of the course introduces the methodology for the course and some of the fundamental theorems in public choice theory. Part 2 presents the different economic theories of regulation and optimal allocation of regulatory power. Part 3 concludes examining four different methods of lawmaking, described respectively as: (1) lawmaking through legislation (codified law); (2) lawmaking through adjudication (judge-made law); (3) lawmaking through practice (customary law); and (4) lawmaking through agreement (treaty law). The readings and class analysis aim at providing a birds-eye view on public choice and regulation theory from an economic perspective. The readings will shed new light on the important issue of the institutional design of lawmaking, emphasizing the respective advantages and proper scope of application of legislation, judge-made law, customary law, and treaty law in the creation of a legal order.