Introductory Texts in Natural Law, Roman Law, and Canon Law

At the request of a reader, we at Ius & Iustitium have drawn up a list of introductory texts in natural law, Roman law, and canon law, as well as a few on legal history. Natural law and Roman are unfortunately no longer commonly taught, and certainly not required, as a part of American legal training. Canon law, despite its influence on the development of common law, is unlikely even to be touched upon. Despite their reputation as arcane and recondite subjects, these are in fact endlessly fruitful and, with even modest application, rewarding areas. It should go without saying that we believe their study is vital to the revival of a common good jurisprudence. 

We have focused on texts that will serve as good introductions for the American-schooled lawyer (or law student) who has never studied these areas before. But although this list is designed for lawyers, most of these works may be read just as profitably by intelligent laymen. We have for the most part avoided primary sources in this list, preferring introductory texts here.

Natural Law

  • Thomas Aquinas, Treatise on Law ST I-II, q. 90-108. Although this list is not a bibliography of primary sources (that will be left for a separate post), and focuses on secondary texts, pride of place must be given to Aquinas’s Treatise on Law, and this for two reasons: First, the treatise is unusually clear and lucid, even for a thinker renowned for his lucidity. Hence, with a bit of work, it may be read as profitably by the determined beginner as by the seasoned expert. Second, the Treatise on Law is absolutely central to virtually all accounts of natural law. Any attempt to properly understand natural law must reckon with it sooner or later. It is best that it be done sooner to avoid falling into error.
  • Brian McCall, The Architecture of Law: Rebuilding Law in the Classical Tradition. One of the best expositions of the natural law to come out in recent years. In it, McCall shows the superiority of the classical natural law tradition over the legal positivism that is so in vogue today. As such, it has value for everyone interested in the natural law tradition, and is particularly suitable for lawyers trained in the common law tradition who have not previously had a systematic exposure to the natural law tradition. 
  • Heinrich Rommen, Natural Law: A Study in Legal and Social History and Philosophy. An introductory study of the philosophical history of natural law theory from the ancients through the moderns. Rommen draws critical attention to the manner in which Enlightenment thinkers such as Hobbes and Locke distorted the classical tradition while also analyzing the rise of legal positivism and its negative consequences.
  • Javier Hervada, Critical Introduction to Natural Law. A canonist and legal philosopher by training, Hervada taught both disciplines, as well as natural law, at the University of Navarra. He is one of the great systematizers of the Thomistic doctrine of juridical realism against the upsurge of positivism in the second half of the 20th century. His Introducción crítica, written for jurists and available in English, develops the doctrine of natural law as a juridical system based on the concept of right as the object of justice, i.e., as ‘the what is owed to another.’
  • Javier Hervada, What Is Law? The Modern Response of Juridical Realism. This little book summarizes the basic tenets of a Thomistic, natural-law jurisprudence in a straightforward, dogmatic style. Written for first-year law students, it is an excellent introduction for people with little to no legal training.

Roman Law

  • Barry Nicholas, An Introduction to Roman Law. This is the standard English language introduction to Roman law. It offers a magisterial account of Roman private law, tracing its history from the twelve tables up through modern times. 
  • Ernest Metzger, A Companion to Justinian’s Institutes. An excellent and lucid companion to Justinian’s Institutes—specifically designed to accompany the translation by Peter Birks and Grant McLeod. The Institutes are the well-spring of Roman law, and remain the best introduction to the subject. 
  • John Henry Merryman, The Civil Law Tradition. Merryman famously quoted a nameless scholar as saying that if he were innocent, he would prefer trial at a civil law court; if guilty, at a common law court. This classic introduction to the civil law tradition explains why, in Merryman’s view and those of others, the disparity of legal procedure is of such crucial importance.
  • Buckland & McNair, Roman Law and Common Law: A Comparison in Outline [2nd edition]. First published in 1936, Buckland’s Roman Law and Common Law compares the sources and methods of these two great legal systems before outlining their view of the law of persons, the law of property, succession, obligations, delict and tort, and procedure. Now in an expanded and supplemented edition, Roman Law and Common Law provides a helpful comparative introduction.
  • Rafael Domingo, Roman Law, An Introduction. Domingo trained as a Romanist, a specialist in Roman law, under Álvaro d’Ors, one of the greatest jurists of the 20th century. He has also written on legal philosophy, international law, constitutional law, civil law, and others. His Introduction presents a brief overview of the sources, methods, and history of Roman law.

Canon Law

  • Javier Hervada, Introduction to the Study of Canon Law. Hervada developed a general theory of canon law, including in the areas of canonical constitutional law and the law of matrimony, based on his articulation of natural-law jurisprudence, that has been highly influential in certain sectors. This work prepares the reader for the study of canon law by introducing first the role of law in the life of the Church, followed by a review of a number of categories and concepts essential to all juridical science.
  • R. H. Helmholz, The Spirit of Classical Canon Law.  Drawing on the fundamental sources of medieval canon law, R. H. Helmholz present a dozen legal vignettes that together capture “the spirit of classical canon law.” Chapter 13, for example, sketches a scenario of how the courts of church and state interacted procedurally in medieval England. Other chapters explain how oaths worked in canon law, and distill some of Helmholz’s groundbreaking research on the canonical origins of modern criminal procedure. 

Legal History

  • Paolo Grossi, A History of European Law. Grossi is a former president of the Italian Constitutional Court and professor of the History of Medieval and Modern Law at the University of Florence, and one of the most renowned living legal historians. A History of European Law is a mature summation of his work in less than 200 pages that provides an excellent, high-level overview of the history of Western law since the Middle Ages.
  • R. H. Helmholz, The Ius Commune in England: Four Studies. The ius commune was the system of jurisprudence founded upon Roman law and canon law that was nothing more or less than the jurisprudence of Christendom. Helmholz’s book uses four examples—including the law of sanctuary and the question of civil jurisdiction over the clergy—to explore the influence of the ius commune on Anglo-American law. Such exploration is helpful to develop an understanding of the canonical and Roman influences on modern Anglo-American concepts.