Introduction
Secondary sources do the initial legwork of researching the law for you by citing primary and secondary authorities related to an area of law, and they often explain that area of law more thoroughly than would a single case or statute. There are several types of secondary sources, below is a brief list of the basic sources.
*Credit: Lexis Secondary Sources Toolkit
Types of Secondary Sources
- Legal Dictionaries - Contain definitions of legal terms.
- Legal Encyclopedia - Contain an alphabetical summary of major legal topics
- Legal Periodicals - Contain articles written on various legal topics
- American Law Reports - Annotations include a summary of a narrow legal topic along with a multijurisdictional table of laws
- Legal Treatises - Provide in-depth commentary on a specific legal topic
- Restatement of the Law - Codify common law and can become binding if adopted
Legal Dictionaries
What is a Legal Dictionary?
A legal dictionary contains the definitions of legal terms taken from a variety of sources. They are the first place you should look when you do not understand what a legal term means.
Two of the most commonly used legal dictionaries are:
Why use a Legal Dictionary?
In addition to providing a general definition of the legal term in question, legal dictionaries may also provide references to applicable primary law and other secondary sources containing more in-depth discussions of the term.
Legal Encyclopedia
What is a Legal Encyclopedia?
A legal encyclopedia is a comprehensive set of brief articles on legal topics. It is arranged similarly to a general encyclopedia with topical articles arranged in alphabetical order. In the final volume(s) of most legal encyclopedias is an index.
The two most popular general legal encyclopedias are:
- Corpus Juris Secundum (Westlaw) - CJS is divided into about 400 topics, which are subdivided into subtopics and sections. Each section contains a brief “blackletter” statement of the law, followed by a short section of text. The footnotes reference federal and state cases, and West topics and key numbers are included with references to secondary sources. CJS also has a multi-volume index at the end of the set, a separate volume that is a Table of Laws and Rules, and a Table of Cases. CJS is also updated with pocket parts.
- American Jurisprudence (Lexis) - AmJur provides broad overviews of legal topics, identifies specialized vocabulary, and provides citations to primary and secondary materials, including ALR annotations. Each topic in AmJur begins with a detailed scope note, general cross-references and an outline of the topic. Relevant sections in AmJur can be found by using the General Index volumes located at the end of the set. There is also a separate volume called the Table of Laws and Rules which provides topics and sections in AmJur which cite a particular federal statute, regulation, or procedural rule. AmJur volumes are updated with pocket parts.
In addition, there are numerous state legal encyclopedias.
Why Use a Legal Encyclopedia?
First, the articles can be quite useful as a general introduction to an area of law that is new to you. They provide more in-depth information than a legal dictionary while being nearly as accessible and easy to use.
Second, encyclopedias are a way to find citations to cases and other useful materials on a particular issue.
Using a Legal Encyclopedia
Using a legal encyclopedia is straightforward: look up your topic in the index, identify the section or sections where your topic is discussed, turn to those sections, and read them. Both can be accessed online through Westlaw and Lexis.
Legal Periodicals
What is a Legal Periodical?
Legal periodicals contain articles about emerging areas of law and are written by professors, practitioners, judges, and law students. Commonly used legal periodicals include law reviews, law journals, and bar journals.
Why Use a Legal Periodical?
Legal periodicals are often the first secondary source to cover new and emerging areas of law and to highlight developments and changes in the existing law. In addition to providing an in-depth discussion on the legal issue, a law review or journal article also will provide citations to significant, and often recent, primary and secondary sources.
Periodical Index
A periodical index collects information about individual articles that appear in journals, newsletters, and magazines. That information is arranged alphabetically by title, author, and subject.
American Law Reports
What is an A.L.R. Annotation?
ALR contains annotations, which are articles written by legal experts on very narrow legal issues. These annotations are based on cases that represent emerging, unsettled, ever-changing areas of the law, and they provide an objective analysis of the current state of the law in this area. Annotations explore the law of the jurisdictions that have dealt with this issue and cite to cases on all sides of an issue.
Why Use an A.L.R. Annotation?
If you find an A.L.R. covering your topic, it is a great starting point for research. In addition to providing a summary of the legal issue, the Table of Cases, Laws, and Rules gives you a snapshot of the law across jurisdictions (federal, state, and foreign). A.L.R. annotations also identify other secondary sources, such as legal encyclopedias, treatises, and periodicals.
Using an A.L.R. Annotation
For online access:
ALR Index
There is a multi-volume ALR Index that can help you find annotations by subject. There is also a one-volume Table of Laws, Rules, and Regulations that can help you find annotations that cite particular federal statutes, regulations, and court rules, as well as state statutes and constitutions.
Legal Treatises
What is a Treatise?
Treatises are books that provide in-depth treatment, usually on a single subject, such as torts or constitutional law. Treatises usually provide an overview of the subject as well as analysis and commentary. They also frequently contain citations to many primary and secondary sources. Treatises range from broad, multi-volume sets to narrowly focused one-volume titles.
Why Use a Treatise?
Practitioners rely heavily on treatises for the detailed coverage and practical tips they contain.
Finding Treatises
You can locate relevant treatises by keyword searching in the Polar Catalog.
For Online access:
See the example below from Understanding Immigration Law regarding the English language requirement.
Restatements of the Law
What are Restatements of the Law?
Restatements of the Law are a series of treatises that articulate the principles or rules for a specific area of law. They are secondary sources of the law written and published by the American Law Institute (ALI) to clarify the law.
Why Use Restatements?
They are the most persuasive secondary source because they can become binding law if adopted by a jurisdiction. The main volumes contain statements of the common law rules, whereas the appendices contain lists by jurisdiction of cases applying the corresponding rule.
Restatements (Online)
Restatements have a subject index to find specific topics and also have Appendix volumes containing summaries of cases that have cited the Restatement.
Restatements have a subject index to find specific topics and also have Appendix volumes containing summaries of cases that have cited the Restatement. See examples below.
Online Legal Periodicals
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