This book offers a philosophical analysis of the role played by legal scholarship in the written judicial decisions of different Western legal systems. Based on a positivist (and, more specifically, Hartian) theory of law, the book discusses the concept of a source of law and the possibility of including within that concept the writings of legal scholars. It also discusses the concept of authority and the structure of authority-based arguments, such as those that judges often employ when referring to legal scholarship in their judgments.