Duncan Kennedy is one of the most prominent and influential legal theorists of the day. This is a major effort summarizing, clarifying, and elaborating his views on the core questions of jurisprudence. Kennedy's argument is about the political nature of legal, and especially judicial, decisionmaking. It follows directly and self-consciously in a centuries-old line of debate that has been especially intense in the United States throughout much of the twentieth century. The two principal books with which to compare Kennedy's in recent decades are H.L.A. Hart's The Concept of Law and Ronald Dworkin's Law's Empire. Kennedy's book deserves to be as popular as they have been.