Book excerpt: This book proposes a rather novel legal-philosophical approach to understanding the intersection between law and morality. It does so by analyzing the conditions for the existence of a juridical domain of natural law from the perspective of the tradition of Thomistic juridical realism. In order to highlight the need to reconnect with this tradition in the context of contemporary legal philosophy, the book presents various other recent jurisprudential positions regarding the overlap between law and morality. While most authors either exclude a conceptual necessity for the inclusion of moral principles in the nature of law or refer to the purely moral status of natural law at the foundations of the legal phenomenon, the book seeks to elucidate the essential properties of the juridical status of natural law. In order to establish the juridicity of natural law, the book explores the relevant arguments of Thomas Aquinas and some of his main commentators on this issue, above all Michel Villey and Javier Hervada. It establishes that Thomistic juridical realism observes the juridical phenomenon not only from the perspective of legal norms or subjective individual rights, but also from the perspective of the primary meaning of the concept of right (ius), namely, the just thing itself as the object of justice. In this perspective, natural rights already possess a fully juridical status and can be described as natural juridical goods. In addition, from the viewpoint of Thomistic juridical realism, we can identify certain natural norms or principles of justice as the juridical title of these rights or goods. The book includes an assessment of the prospective points of dialogue with the other trends in Thomistic legal philosophy as well as with various accounts of the nature of law in contemporary legal theory.