Precedent is a central feature of legal practice, requiring courts to follow decisions reached in earlier cases, thereby transforming the decisions in individual cases into a source of law. This article examines two major questions associated with precedent: (a) how to characterise the way that precedent operates as a source of law; and (b) how to justify the requirement that courts follow earlier decisions regardless of the merits of those decisions. Precedents are often thought to create general legal rules, but it is controversial whether this is the best way to understand their role in legal reasoning. Equally, it is unclear that the most common justifications for precedent unequivocally vindicate the practice.