Subject headings are specific, predefined terms that the Library of Congress assigns to printed material. Because they use a "controlled vocabulary," subject headings typically do not include multi-disciplinary or complex topics.
It's most useful to start with a keyword search in the Library Catalog, using a combination of terms that describe your topic. Once you have located a relevant item, you can look at the Subjects in the record and follow those links to find related books. Below are examples of subject headings
Unlike Subject Headings which use a precise, controlled vocabulary, Keywords are your own search terms that best express the essence of your topic.
Advantages to using keywords:
Disadvantages of using keywords: