As you have learned throughout this week, secondary sources describe and interpret the law. They also provide citations to relevant primary authority. Secondary sources vary in their depth and coverage of legal topics. In some cases, secondary resources summarize a legal issue very broadly (as in law dictionaries and encyclopedias); others, such as treatises, restatements, and journals, are very in-depth and specific in their coverage. Keep in mind that many legal issues are complex and require multiple secondary sources. Thus, it may be necessary for a researcher to utilize many sources in order to gain complete familiarity with a policy or legal issue.