Allan Beever lays the foundation for a timely philosophical and empirical study of the nature of law with a detailed examination of the structure of evolving law through declaratory speech acts. This engaging book demonstrates both how law itself is achieved and also its ability to generate rights, duties, obligations, permissions and powers.Structured into three distinct parts - the philosophy of law and jurisprudence, the structure of the social word and the ontology of law, and the reconstruction of the philosophy of law - the author provides insight into law as a human institution and reveals that central debates are often based on misunderstandings of interpretation and intentionality. Inspired by the philosophy of John Searle alongside other well-respected legal theorists, the author also analyses both sides of the mainstream jurisprudential divide in its current state, in particular the theory of legal positivism.Examining all aspects of law and answering the important question of ‘What is Law?’, this book will be an invaluable resource for academics and advanced students in law schools and philosophy departments.