Secondary sources provide commentary and background information on the law and can point you towards useful primary sources. However, they are not actual law.
Unlike primary legal sources, secondary sources are generally not binding on courts (for an exception see Restatements, below). You may cite secondary sources in a memorandum or article when you wish to provide the reader with a more in-depth explanation of a topic.
It is a good idea to begin your research with secondary sources, especially if you are researching a topic you do not know well. Since secondary sources use primary sources as the basis for their discussion, looking at the primary sources referenced in a secondary source (cases, statutes, regulations, etc.) will provide you with an excellent basis from which you can begin analyzing and applying the law in that area.
Using secondary sources can be somewhat complex due to the variety of secondary sources available and the fact that each is organized somewhat differently.
The rest of this page describes various types of secondary sources in both print/online and how to use them effectively.
Legal dictionaries are useful because the legal definition of a term will often differ from the non-legal definition of a term. During the research process, look up terms you encounter to verify that your interpretation of the word is correct.
Legal encyclopedias provide very general information on a large number of topics, and can be used as a finding tool for primary authority.
When providing a Bluebook citation to an encyclopedia article, use the full article name (e.g., Searches and Seizures) followed by the section number and then the year of publication.
Example: 67A Am. Jur. 2d Sales § 940 (2003).
Additional examples are under Sample Bluebook Citations.
A treatise is a work that extensively covers one topic.
Many -- but not all -- treatises are regularly updated. It is important to determine the age of any treatise you are considering using, especially if you are looking for current information.
Sometimes you need to identify the state of the law at an earlier time. In these instances older editions of a treatise can be very useful.
Treatises are also available online in Bloomberg Law, Lexis Advance, the Lexis Nexis Digital Library, and Westlaw. Other publishers such as Wolters Kluwer and BNA also offer treatises online.
The term "periodicals" encompasses several types of publications that discuss trends and developments in the law. There are 5 general forms of legal periodicals:
The following types of publications are more practice-oriented and provide current information of interest such as docket information, rule changes, and current court decisions.
HeinOnline contains a variety of legal periodicals but also contains many other types of resources, so a general search in Hein may bring up many non-periodical materials. To limit your search to articles, try searching within these specific collections:
Legal databases such as Bloomberg Law, Lexis Advance and Westlaw all contain legal periodicals. Usually these will be located within "Secondary Sources" in each database.
American Law Reports (ALRs) contain articles, called "annotations,"* which provide in-depth information about the case law (and statutes when relevant) related to a particular topic across multiple jurisdictions (both state and federal). (Note: the word "annotation" as used in the ALR is used in an entirely different sense from the "annotations" you will see in annotated, statutory codes.)
Remember that the ALR annotations are simply compilations of references and summaries of materials. You must still locate and read the full text of the referenced cases and statutes and draw your own conclusions about the materials. Do not rely solely on the summaries in the ALRs.
There are several "series" of ALRs. The best way to search them, both online and in print, is by using the index.
Restatements are published by the American Law Institute. The purpose behind their creation was to unify topics in common law such as Contracts, Torts, and Property on a national basis. Restatements are created and revised by groups of experts in a particular discipline.
Tips for using Restatements online:
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