Subject Headings Tips
Subject headings are a great way to use the library's catalog to locate relevant materials. They are created by the Library of Congress, and you are not expected to know these terms by heart, but they are the best way to focus your research. I suggest doing a Keyword search as a starting point. For example, a keyword search on civil war will give you a long list of books that mention civil and war in the record. But what civil war do you mean? (U.S. civil war? Spanish civil war? etc.) Look at your results and find a book that is close to your topic. (eg. Spanish Civil War) Look at the catalog record and you will see the subject headings linked at the bottom. By clicking on those links, you will be directed to the books that fit that subject. Give it a try!
Searching for primary sources? Look for subjects with "sources", or "correspondence" or "personal narratives" (eg. United States History 1849-1877 Sources or Lincoln, Abraham - correspondence). Or try searching for your subject as an Author (eg. Stalin, Joseph) to find all material they may have written. That's a primary source also!