Legality is a profound work in analytical jurisprudence, the branch of legal philosophy which deals with metaphysical questions about the law. In the twentieth century, there have been two major approaches to the nature of law. The first and most prominent is legal positivism, which draws a sharp distinction between law as it is and law as it might be or ought to be. The second are theories that view law as embedded in a moral framework. Scott Shapiro is a positivist, but one who tries to bridge the differences between the two approaches. In Legality, he shows how law can be thought of as a set of plans to achieve complex human goals. His new "planning" theory of law is a way to solve the "possibility problem", which is the problem of how law can be authoritative without referring to higher laws.