A written constitution and judicial review—giving a court the power to review ordinary legislation for compliance with the written constitution, are the two most successful exports of American governance to the rest of the world. To what extent are these innovations historically and conceptually indebted to the English common law tradition, with its emphasis on judge, jury, and custom, as opposed to canonical written documents? Are they grounded, at all, in the other great Western legal tradition in which texts are more important—the civil law, which in turn largely “received” Roman law? What exactly are common law, civil law, Roman law, and what are the basic differences among them? Prior coursework in Roman law, civil law, or common law, is not presumed; foreign LL.M. and S.J.D. students are welcome.