Usually, legal research has a clear progression which stems from its very nature. You start with a plan which maps out your understanding of the question and how you think you should answer it. Then, you identify the secondary sources which you believe are most relevant to your research. Finally, once you understand the contextual background information, you move from secondary sources to primary sources: the statutes, case laws, or administrative rules.

But legal research is not merely a mechanical process. It involves a continuously revolving door from secondary to primary sources, and then from one repository of primary sources to another. Often you start with a treatise, then you read a case, then a law review article, and then locate another case. The issue I will tackle in this section is how to find the most reliable collection of primary sources in the most efficient manner possible. I call those collections of primary sources "repositories" because I want to emphasize their tangibility.

Legal information is extremely hierarchical. Thus I will start by identifying legal repositories in descending order according to their authoritative role in the American legal system: the federal Constitution; federal or state statute or municipal ordinance; court decisions; and finally, administrative rules, regulations, and decisions. Some repositories contain only laws from one branch of the government. Others are an amalgamation of primary sources, and even secondary sources. More noteworthy, only some repositories allow the researcher to update the results of their research and assure that the law has not been overturned. Because updating is the last necessary step of any reliable legal research process, the choice of repository is often dependent upon its research features.