Primary sources, particularly statutes and regulations, do not provide explanations like secondary sources. Start your research with secondary sources to better understand the legal principles at issue and to locate additional relevant law.
American Law Reports (ALR)
Restatements of the Law
Law Journal Articles
Case law refers to the reported decisions (or "opinions") of courts, which interpret existing law based on a specific set of facts. Judges look to past decisions for guidance in ruling on cases.
Generally speaking, the decisions of higher courts are binding on lower courts in the same jurisdiction when similar issues are raised. When a court has jurisdiction over a matter, it is authorized to hear the case and possibly pronounce judgment. Federal courts and state courts have jurisdiction over different matters, while small courts (like probate or traffic court) have limited jurisdiction. [For a brief explanation of when court decisions are binding, see Mandatory vs. Persuasive Cases, by Barbara Bintliff. For a short explanation of the differences between federal and state courts, see Federal vs. State Courts--Key Differences, from FindLaw.]
For example: Dixon v. Alabama State Board of Education, 186 F. Supp. 945 (M.D. Ala. 1960)
Published case law mostly consists of the decisions of appellate courts and courts of last resort (e.g., the Supreme Court). Since trial court decisions are not binding on other courts, they are usually not published.
Judicial opinions typically include the following components:
Statutes are laws passed by a legislative body, e.g., the U.S. Congress. Statutes typically go through the following publication life cycle:
There is more than one way to identify a statute.
Administrative regulations are promulgated by government agencies under the authority delegated by Congress. For more information about federal regulations and agency's rulemaking power, see Treatise Finder for Administrative Law.
The Federal Register is the chronological publication of proposed regulations, final regulations, and related materials, published weekly. The Code of Federal Regulations (CFR) is a subject arrangement of regulations. A regulation will be published first in the Federal Register and will later be included in the appropriate volume of the CFR.
Like cases and statutes, regulations are found through citations.
Other Administrative Materials
While many official documents produced by administrative agencies are found in the Federal Register, others are published by the agency itself. Administrative Orders and Decisions by agency heads are often more likely found on the agency's website.
A fundamental issue of legal research is knowing what jurisdiction is relevant to your case.
Federal vs. State
The two major court systems in the United States are the federal courts and the state courts. They each have their own precedents, hierarchy, rules, and other characteristics.