This classic collection of essays, first published in 1979, has had and continues to have a major influence on philosophical work on the nature of law and its relation to morality. The author begins by examining the concept of authority and the law's claim to moral authority. He then offers a detailed explanation of the nature of law and legal systems, arguing for legal positivism. He then considers areas of legal thought that have been considered to be imbued with moral values, namely the social functions of law, the ideal of the rule of law, etc.

The book concludes with a discussion of the proper moral attitude of the citizen to the law. Raz raises the question of whether citizens have a moral duty to obey the law and whether there is a right to dissent. In two appendices, he develops his views on the nature of law, engaging with the work of Hans Kelsen and responding to Robert Alexy's critique of legal positivism.