The UIUC Library is one of 70+ member libraries comprising the I-Share consortium. I-Share libraries share an online catalog, Illinet Online, and UIUC students, staff, and faculty can borrow directly from the other libraries in the consortium by placing a request through the catalog.
Books and journals are organized in the library by subject. Each item is assigned one or more subject headings and a unique call number. Subject headings are standardized terms generated by the Library of Congress. The call number is based on the Dewey Decimal Classification.
Subject heading searches are more comprehensive and more precise than keyword searches. It's true that you can find sources on a topic by doing keyword searches. But if you limit yourself to keyword searching, you are likely to miss important material on your topic that uses other terms. If you only need a few books, you can probably find what you need by doing keyword searches, but if you are doing historical research, you can't afford to miss critical material on your topic. For best results, search with subject headings as well as keywords.
A good way to identify subject headings for a topic is to start with a keyword search in the online catalog using terms you think describe the topic and try to identify a few relevant books. Look at the full record for those books to see what subject headings were used, then do another search on those headings.
As a rule of thumb, use fairly broad headings, as well as the specific ones that describe your topic, in order to make sure you haven't inadvertently eliminated relevant material that is contained within works of larger scope. In all likelihood you will find multiple headings to describe your topic, and you should use all of them. You can narrow your search in the online catalog by combining subject headings (as a phrase) with keywords, using the "Advanced Search" option.
Do an Advanced Search on the terms "cross dressing" and "medieval" to find books on this topic. ("Cross dressing" is not a Library of Congress subject heading.) Then look at the subject headings in the catalog record for those books (Costume-History---Medieval, 500-1500 or Gender identity in literature or Sex role-Europe-History-To 1500, for example). Then do a Quick Search on those subject headings to find more books on the topic.
Do an Advanced Search on the keyword phrase "cultural hegemony." Or try an Advanced Search combining the keyword "culture" with the subject heading "Imperialism." Try an Advanced search on the phrase "American empire." Or try an Advanced Search on the keyword phrase "new imperialism" with the subject heading "United States." Look at the subject headings used in the records for any books that seem to cover your topic, then do a Quick Search on those subject headings for more books.
Do a "Quick Search" when you have the exact form of the subject heading and want to find more books with that heading (e.g., Cities and towns in literature), to search a title when you know exactly how it begins (e.g., Slaves on Screens), to locate a work or works by a particular author (e.g., Julie Buckler), or to search by call number for a specific book (e.g., 700.89924043 B455) to find out where it is located in the UIUC library system.