There are 4 major ways to find case law based on the subject. Searching for cases using some of the following methods can be pretty complicated. It may be a good idea to seek instruction from a knowledgeable librarian before you try any of them.
#1 - Read articles or books about the topic
The first way is to read articles or books about the subject you are researching to see if they refer to cases. For most people, this is the best place to start your research. Look for articles or books by reputable authors who are attorneys or judges. Read the article carefully. Usually, the articles will discuss one or more cases and explain the patterns of the law applied to the cases. The closer that the facts in a case match your situation, the more likely the case will be helpful to you. The benefit of using an article/book to start your case research is that the author presumably has done some analysis and research on the topic. Be careful with the date of the article. You can assume that the author last did his/her research at least a month or two before the publication date. No cases since that day will be included, meaning, any cases that have been heard since the article was written which changed the law will not be reflected in the article.
Some of the articles on the Peoples Law Library identify relevant cases. Law libraries have books and encyclopedias that talk about many other areas of law not covered here.
#2 - Look at the "annotated" version of the law
The second way, if you have already found a relevant statute, is to look at that statute in an annotated version of the statutory code for the jurisdiction you are researching.
- Maryland case law - For example, if you are researching Maryland law and you have already found a statute that applies to your situation by searching the Maryland Code database on the web, you could then go to a law library and look that statute up in the Annotated Code of Maryland. At the end of statute you would find summaries of cases that interpreted the statute. These cases usually deal with the same subjects as the statute. The summaries also give citations to case reporters where you could look up the full text of the cases.
- Federal case law - If you are researching federal law instead of Maryland law, you can find cases in the same way. Two of the three print versions of the United States Code provide case annotations after the text of each statute. The two versions of the code that include case annotations are the United States Code Annotated and the United States Code Service.
#3 - Use a case digest
The third major way to find case law by subject is to use a case digest. A digest is basically a subject index to case law that also gives you summaries of the cases indexed. There are different case digests for different legal jurisdictions. For example, if you want to find Maryland case law, you should search the Maryland Digest. If you want to find federal case law, you should search the Federal Practice Digest, which is now in its fourth series.
#4 - Search by subject in a database, once you have found the cases
The fourth major way to find case law by subject is to search a full text database of case law from your jurisdiction. In order to do this, however, you will have to find a library that has a publicly accessible subscription to such a database. Most public law libraries have such subscriptions. Be careful with the free case law databases that you find on the Internet, most of them only include cases decided in the last 6 to 8 years. Cases decided more than 8 years ago may still be binding law. Cases remain valid until they are overruled or the statute or regulations change.
Once you have found cases that apply to your legal problem, you have to make sure that they have not been reversed or overruled since they were originally decided. To do this, you will need to use a "citator" - a service that lists cases that have cited your case since it was decided. The most popular citator service is Shepard's Citations, which is available in print and on the web. The print version of Shepard's is extremely difficult to use and generally several weeks out of date. The web version is much easier to use, but requires a subscription or payment by a credit card. Many, but not all, public law libraries have subscriptions to the web version of Shepard's that allow members of the public to use the service from a library computer. Before you go to the library, call to see if your local library has the web version of Shepard's available to the public.