This volume investigates the fundamental criteria for the existence and structural integrity of a legal system. Joseph Raz, a prominent legal philosopher, utilizes a rigorous analytical framework to evaluate how laws are identified as belonging to a specific system. By engaging with the works of legal theorists such as Bentham, Austin, Kelsen, and Hart, Raz constructs a systematic approach to understanding the necessary relations that define the internal logic of law.

Legal scholars and students of jurisprudence frequently cite this work as a foundational text for understanding the structural components of law. Readers often note the academic density of the prose, which requires a high level of familiarity with analytical philosophy and legal theory.