# Index of law articles
An **index of law articles** is a finding aid that serves readers who know a legal term but not where it is treated, sitting alongside the tools legal researchers use to move from a topic to the authorities that decide it.[1](https://www.law.cornell.edu/wex/Legal_research) Unlike an alphabetical encyclopedia, which summarizes the law and supplies citations a researcher can follow, an index points to where a term is treated.[2](https://guides.loc.gov/law-secondary-resources/legal-encyclopedias) It functions within a broader set of research tools that includes legal encyclopedias, treatises, American Law Reports, and periodical indexes such as the Index to Legal Periodicals.[1](https://www.law.cornell.edu/wex/Legal_research)
Indexes of this kind serve readers who know a term but not where it is treated, and they sit alongside the finding tools that legal researchers use to move from a topic to the authorities that decide it.[1](https://www.law.cornell.edu/wex/Legal_research)
| Key fact | Detail |
|---|---|
| Companion reference works | Legal encyclopedias offer broad commentary on federal and state law; the two major US titles are American Jurisprudence (Am. Jur.) 2d and Corpus Juris Secundum (CJS)[2](https://guides.loc.gov/law-secondary-resources/legal-encyclopedias) |
| Periodical indexes | Index to Legal Periodicals & Books Full Text covers over 1,000 legal journals from six countries; LegalTrac indexes more than 2,400 titles[3](https://wwws.loc.gov/law/find/databases.php) |
| Legal taxonomies | The Legal Services Corporation's NSMI provides a centralized taxonomy of Americans' legal issues, and the LIST controlled vocabulary for civil legal problems holds 1,301 terms in 20 categories as of June 16, 2026[4](https://www.law.georgetown.edu/tech-institute/wp-content/uploads/sites/42/2022/06/Data-Commons-Models.pdf) • [5](https://www.taxonomy.legal/) |
| Limits of encyclopedia use | Legal encyclopedias are not intended as authoritative sources and are not cited in briefs, memoranda, or scholarly papers[6](https://guides.ll.georgetown.edu/secondary/encyclopedias) |
## Scope and arrangement
[Alphabetical order](https://www.edgepedia.org/alphabetical-order) is the standard arrangement for legal encyclopedias as well, which are described as comprehensive sets of brief articles on legal topics arranged like a general encyclopedia, with a topical index in the final volumes of the print sets.[6](https://guides.ll.georgetown.edu/secondary/encyclopedias) A flat index and an alphabetical encyclopedia serve different purposes: the index points to where a term is treated, while the encyclopedia article summarizes the law and supplies citations a researcher can follow.[2](https://guides.loc.gov/law-secondary-resources/legal-encyclopedias)
## Role in legal research
Finding tools are central to legal research because the body of authority is large and layered. Researchers commonly begin with summaries of an area of law, such as legal encyclopedias, treatises, and American Law Reports, and then use indexes such as the Index to Legal Periodicals to locate law review and periodical interpretation of particular topics.[1](https://www.law.cornell.edu/wex/Legal_research) The citations and annotations carried by these secondary tools are an important element of their value, since they direct the reader toward the primary authorities that decide the question.[1](https://www.law.cornell.edu/wex/Legal_research)
**Why a starting point matters.** Library guides describe legal encyclopedias as useful for two purposes: as a general introduction to an area of law new to the researcher, and as a way to find citations to cases and other materials on a particular issue.[6](https://guides.ll.georgetown.edu/secondary/encyclopedias) [Encyclopedia](https://www.edgepedia.org/encyclopedia) articles focus mainly on case law and are kept current with pocket parts or supplements in print.[2](https://guides.loc.gov/law-secondary-resources/legal-encyclopedias)
## Related indexes and databases
**Periodical indexes.** Several large indexes catalog legal scholarship by subject. The Index to Legal Periodicals & Books Full Text (1981 to present) covers over 1,000 legal journals, yearbooks, and law reviews from the United States, Canada, Great Britain, Ireland, Australia, and New Zealand, and the retrospective Index to Legal Periodicals Retrospective (1908 to 1981) covers more than 750 legal periodicals.[3](https://wwws.loc.gov/law/find/databases.php) Indexes list bibliographic information about each article: title, author, journal name, volume, issue, page number, date, and subject headings.[3](https://wwws.loc.gov/law/find/databases.php) The EBSCO edition of Index to Legal Periodicals & Books reports 1,480 active indexed and abstracted journals, of which 1,370 are peer-reviewed.[7](https://about.ebsco.com/products/research-databases/index-legal-periodicals-books)
**Comparative and foreign-law finding aids.** For research across jurisdictions, the Index to Foreign Legal Periodicals is a multilingual subject index to legal articles and book reviews published in over 550 sources worldwide.[3](https://wwws.loc.gov/law/find/databases.php) *Multinational Sources Compared: A Subject and Jurisdiction Index*, available in print and as a searchable HeinOnline database, helps researchers identify print and electronic resources that compare jurisdictions; its third edition contains 107 new sources, 252 updated sources, and coverage of 367 legal subjects.[8](https://heinonline.com/multinational-sources-compared/)
## Subject classification of law
An alphabetical index lists terms without imposing a structure on them; taxonomies and classification schemes do impose one, and the difference matters for retrieval. A controlled vocabulary is the set of agreed-upon terms that comprise the taxonomy of topical classifications used for subject-based searching in legal databases.[9](https://ecampusontario.pressbooks.pub/legalresearchonline/open/download?type=print_pdf) [Classification](https://www.edgepedia.org/classification) systems face known difficulties, including subjectivity in assigning categories, overlap between interdisciplinary subjects, and a lag between the evolution of knowledge and the adaptation of the classification.[10](https://lis.academy/organising-and-managing-information/challenges-limitations-classification-systems/)
**Taxonomies for legal aid and practice.** The National Subject Matter Index is a centralized, comprehensive taxonomy of Americans' legal issues promulgated by the Legal Services Corporation so that legal services providers can index relevant topics, with a specific number attached to each category and subcategory.[4](https://www.law.georgetown.edu/tech-institute/wp-content/uploads/sites/42/2022/06/Data-Commons-Models.pdf) LIST (Legal Issues Taxonomy) is a controlled vocabulary for civil legal problems that matches a person's real-life situation to a standard legal code, with 1,301 terms and 20 categories as of June 16, 2026.[5](https://www.taxonomy.legal/)
**Automated classification.** Machine methods now assign legal subjects to documents at scale. A study using a dataset of 6,227 Singapore Supreme Court judgments compared state-of-the-art NLP methods, including topic model, word embedding, and language model classifiers, against traditional statistical models, and found that all approaches performed well with as little as a few hundred judgments.[11](https://arxiv.org/abs/1904.06470) Work on UK case law has combined a new taxonomy with a large language model to classify topics such as summary judgment, where judgments are not originally labeled with keywords.[12](https://arxiv.org/abs/2405.12910)
## Free online alternatives
Several free reference resources cover the same ground as commercial encyclopedias. Wex is a free online legal dictionary and encyclopedia created by legal experts and hosted by the Legal Information Institute at Cornell.[13](https://guides.library.umass.edu/legal/encyclopedias) Nolo's legal encyclopedia offers thousands of free, professionally written and edited legal articles organized under a legal issues index that includes topics such as divorce and family law.[14](https://www.nolo.com/legal-encyclopedia)
## References
1. [Legal research, Wex, Legal Information Institute](https://www.law.cornell.edu/wex/Legal_research)
2. [Legal Encyclopedias, Legal Research: A Guide to Secondary Resources, Law Library of Congress](https://guides.loc.gov/law-secondary-resources/legal-encyclopedias)
3. [Databases & eResources, Law Library of Congress](https://wwws.loc.gov/law/find/databases.php)
4. [Classification Systems (Data Commons Models), Georgetown Law Tech Institute](https://www.law.georgetown.edu/tech-institute/wp-content/uploads/sites/42/2022/06/Data-Commons-Models.pdf)
5. [LIST — Legal Issues Taxonomy](https://www.taxonomy.legal/)
6. [Legal Encyclopedias, Secondary Sources Research Guide, Georgetown Law Library](https://guides.ll.georgetown.edu/secondary/encyclopedias)
7. [Index to Legal Periodicals & Books, EBSCO](https://about.ebsco.com/products/research-databases/index-legal-periodicals-books)
8. [Multinational Sources Compared, HeinOnline](https://heinonline.com/multinational-sources-compared/)
9. [Legal Research Online, eCampusOntario / CanLII](https://ecampusontario.pressbooks.pub/legalresearchonline/open/download?type=print_pdf)
10. [The Challenges and Limitations of Classification Systems, LIS Academy](https://lis.academy/organising-and-managing-information/challenges-limitations-classification-systems/)
11. [Legal Area Classification: A Comparative Study of Text Classifiers on Singapore Supreme Court Judgments, arXiv](https://arxiv.org/abs/1904.06470)
12. [Topic Classification of Case Law Using a Large Language Model and a New Taxonomy for UK Law, arXiv](https://arxiv.org/abs/2405.12910)
13. [Encyclopedias and dictionaries, Law and Legal Studies, UMass Amherst Libraries](https://guides.library.umass.edu/legal/encyclopedias)
14. [Nolo's Legal Encyclopedia](https://www.nolo.com/legal-encyclopedia)
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*Topic: Encyclopedia › Society and history › Law and justice*
*Initially written Sep 17, 2026 · Reviewed: Oct 25, 2026 · Edited: Oct 15, 2026; Oct 25, 2026 · Last review: Oct 25, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license