What is law? This question has preoccupied philosophers from Plato to Thomas Hobbes to H. L. A. Hart. Yet many others find it perplexing. How could we possibly know how to answer such an abstract question? And what would be the point of doing so? In Legality, Scott Shapiro argues that the question is not only meaningful but vitally important. In fact, many of the most pressing puzzles that lawyers confront--including who has legal...