Because both morally deficient and morally-minded citizens need rules to help them minimise the errors of unconstrained reasoning, someone must have final authority to determine, by means of general rules, what should be done in a wide range of legal cases. In The Rule of Rules Larry Alexander and Emily Sherwin examine this central role of authoritative rules in settling moral controversies within a society that tends to resist unquestioning obedience to authority. In the process, they help to resolve some of the great debates of modern jurisprudence. Once the importance of rules is understood, the authors claim, the moral and practical dilemmas posed by authoritative rules become the central problems of jurisprudence. Reason dictates that we must follow rules if we wish to avoid destructive error and controversy; however, rules are imperfect, and reason also dictates that we ought not follow rules when we believe they produce the wrong result in a particular case. Given the possibility of erroneous judgement about when the results of rules are wrong, an unavoidable gap exists between what the rule-maker has reason to demand and what his subjects have reason to do. Alexander and Sherwin work through the parallel dilemma that lies at the heart of such ongoing jurisprudential controversies as how judges should reason in deciding cases, what effect should be given to legal precedent, and what status, if any, should be accorded to legal principles. In the end, their rigorous discussion sheds light on such topics as the murky nature of interpretation, the ancient dispute between positivists and natural lawyers, the obligation to obey law, constitutionalism, and the relation between law and coercion. Those interested in jurisprudence, legal theory, and political philosophy will benefit from the edifying discussion in The Rule of Rules.