UPDATE: Comparative Law Research

By Hester Swift

Hester Swift has been Foreign and International Law Librarian at the Institute of Advanced Legal Studies, University of London, since 2007.

Published May/June 2021

(Previously updated by Paul Norman in August 2007, and by Hester Swift in February 2009, in June/July 2013 and in June 2016)

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1. What is Comparative Law?

What is meant by comparative law? In the strict sense, it is the theoretical study of legal systems by comparison with each other, and has a tradition going back over a century. In recent years it has gained in practical importance for two reasons. The first is the increased globalization of world trade, involving the need to conduct business in unfamiliar legal systems. The second is the move towards harmonization of laws, under the auspices of bodies such as the Hague Conference on Private International Law and the European Union. More loosely, there are publications and internet resources that assemble legal materials from several jurisdictions, without necessarily undertaking comparisons, but they can be seen as tools of the trade for comparative lawyers.

2. Comparative Law, Conflict of Laws, and Unification / Harmonization of Law

These three topics are distinct but closely related. Conflict of laws, also referred to as private international law, concerns national or domestic legal rules which are applicable in situations involving the law of another jurisdiction. This may be another country or, in the case of federations, another state.

Unification of law is a process that grew out of the need to simplify conflict of law rules, often by international conventions, and has acted on both the national and international levels. The numerous uniform laws applicable in the United States, most notably the Uniform Commercial Code, are obvious examples.

There are two main sources of international uniform law. First, the Hague Conference on Private International Law first convened in 1893 and has prepared around 40 conventions on subjects such as international civil procedure, including enforcement of foreign judgments; family law, including marriage, protection of children and succession; and product liability.

Second, UNIDROIT, the International Institute for the Unification of Private Law, was set up in 1926 as an organ of the League of Nations but was re-established in 1940 under a new statute. About 60 nations are members. Its most notable convention is the Convention relating to a Uniform Law on the International Sale of Goods, 1964. Under ‘Instruments’ on the website, researchers may find a list of conventions organized by area of law (agency, capital markets, commercial contracts, contract farming, cultural property, factoring, franchising, international sales, international will, leasing, security interests, transnational civil procedure, and transport). Each category offers access to the relevant convention, official commentary, status, preparatory work, depository information, and relevant selected bibliography.

By the nature of its continuing development, the European Union is the center of harmonization activity in Europe. The main thrusts were for many years confined to private law, notably family law, contracts, sales, insurance, trusts and movable property; more recently, following the Treaty of Lisbon, the EU legislators have also moved into the area of criminal law.

European research centers looking at harmonization of law include:

A six-volume draft ‘Common Frame of Reference’ (DCFR) was produced by the Acquis Group and the Study Group on a European Civil Code:

von BAR, C. and CLIVE, E., eds., Principles, definitions and model rules of European private law: draft common frame of reference (DCFR). Oxford University Press, 2010.

A thorough exposition of the idea of a European Civil Code is contained in a collection of contributions from several legal scholars: Towards a European Civil Code, 4th edition, edited by Arthur Hartkamp and others. Kluwer Law International, 2010. Other works on European harmonization include:

For a much fuller discussion of harmonization/uniform law resources, see Duncan Alford’s Guide on the Harmonization of International Commercial Law (updated by Matthew Novak)on this website.

The world’s legal systems are a product of history, largely by conquest and colonization, but also in modern times by reasoned and deliberate adoption by one state of at least part of the legal framework of another. Two important examples are the modernization of Japanese and Egyptian law, and more recently the adoption of western models of commercial, financial and property law in the former socialist countries of Eastern Europe.

We can speak of “families” of legal systems, though increasingly the term “traditions” is being used, highlighting their historical development. The best-known distinction is that between the civil law and the common law traditions. Civil law systems have their foundations in Roman law, but are generally based on codifications produced in Europe in the 19th Century. The most important are the French Civil Code of 1804 and the German Civil Code of 1900. Each was the result of long and careful study by appointed commissions, but they are founded on differing traditions and theory.

Traditional classifications offered by the two classic writers on comparative law (see Books and Journals, below) are:



More recently there has been increasing interest in customary (or chthonic) law. Glenn (see below) gives a new list with a new emphasis: Chthonic, Talmudic, Islamic, Hindu, Asian, Civil law and Common law.

Another relatively new object of study is the mixed jurisdiction, where elements of more than one system are in operation. Examples are Louisiana, Quebec, Scotland, South Africa, and Sri Lanka. Palmer (see below) called mixed jurisdictions the “third legal family,” after common law jurisdictions and Roman-German jurisdictions.

Mattei has proposed a classification into three categories based on the principal source of legal norms: the rule of professional law, rule of political law and rule of traditional law (Mattei, U., ‘Three patterns of law: taxonomy and change in the world’s legal systems,’ (1997) 45 American Journal of Comparative Law 5).

In the first part of this article, I shall mention substantive comparative law sources, and in the second part sources that collect legal materials from many jurisdictions.

3. Books and Journals

3.1. Books

The Elgar Encyclopedia of Comparative Law, edited by Jan Smits,provides an overview of the subject; the second edition was published by Edward Elgar in 2012 and it is available in print or online format.

The seminal British author was Harold C. Gutteridge. The second edition of his Comparative law, originally published by Cambridge University Press in 1949, was reprinted by Wildy in 1974; Cambridge reprinted the first edition (1946) in December 2015.

In the United States, the study of comparative law was pioneered by Rudolf Schlesinger. His Comparative law: cases, text, materials, first published in 1950, is now in its 7th (2009) edition and available from West Academic under the title Schlesinger’s comparative law. While at Cornell University, Schlesinger contributed to the discussions around the drafting of the U.S. Uniform Commercial Code.

Of similar standing is Arthur T. von Mehren, whose work, The civil law system: cases and materials for the comparative study of law appeared in 1957. A second edition, with James R. Gordley, was published in 1977 by Little, Brown.

Other titles include:

3.2. Journals

A more extensive list of comparative law journals has been compiled by Teresa Miguel and others: “Comparative Law: Academic Perspectives”, Appendix A, in The IALL International Handbook of Legal Information Management, Danner, R. A., and Winterton, J., (eds.), Ashgate, 2011 (open access version available from Yale Law School Legal Scholarship Repository).

4. Organizations and Research Institutes

The International Academy of Comparative Law, founded at The Hague in 1924, organizes the International Congress of Comparative Law, which takes place every four years. It produces general and national reports, the national reports being prepared by national committees. The reports are issued by various publishers, usually in the respective country (for example, Belgian national reports are usually published by Bruylant/Larcier). Publication details of recent reports appear on the Academy’s website.

4.1. Selected Organizations and Institutes by Country

For a fuller list of comparative law organizations and research centers, see “Comparative Law: Academic Perspectives ”, Appendices B and C, in The IALL International Handbook of Legal Information Management, Danner, R. A., and Winterton, J., (eds.), Ashgate, 2011 (Yale open access version). See also the American Society of Comparative Law’s list of Corresponding Foreign Institutional Members.

5. Research Guides to Foreign and Comparative Law

6. Published Collections Relating to Several Jurisdictions

6.1. Print

6.2. Web Resources

7. Specific Legal Subjects

Online resources of foreign law on specific subjects are thoroughly covered in Jennifer Allison’s article: Foreign law: subject law collections on the web, on this website.

There are several printed sources that provide the text of national legislation of a range of countries, by subject. For a very useful list, see the Library of Congress’s Global Legal Information Catalogue, based on its own holdings and linking to LoC catalogue entries. One can browse by jurisdiction, subject or title, or search by keyword, jurisdiction, subject, and/or author.

Constitutional Law

Family Law

Labour Law

Intellectual Property

Tax and Commercial Laws