This book brings together leading legal theorists to present original philosophical work on the concept of law - the central question of jurisprudence. It covers five broad topics: firstly it addresses debates concerning the methodology of jurisprudence. In Part II it focuses on the notion of a legal system and its coercive nature, while Part III explores the relationships between law and morality, the traditional point of contention between positivist and non-positivist theories of law. Part IV then examines questions regarding law's normative character and relationships with practical reason. Lastly, the final part introduces two novel theoretical approaches to conceptual jurisprudence.