Different words can be used to describe a subject or topic. When you are looking for a book on the dismissal of employees what words could be used? Dismissal, firing or termination would all be valid. The LC Subjects are standardized lists of words and phrases called controlled vocabulary. That is, only certain words may be used as subject headings which will group all different ways to say the same thing together. To figure out the Library of Congress subject(s) first do a key word search for your term, find a book that looks like a good bet and look at the LC Subjects listed in that record. Then you can use the LC Subjects listed under that book to link to a group of similar books. These can also help you broaden or narrow your topic if you see Birth control — Religious Aspects that is very specific but you can also use just the first part Birth control as a broader topic. LC subject headings are not always the same as commonly used terms, often they are dated or awkward. See the examples below.
Your Words | Library of Congress Subjects |
Movies | Motion Pictures |
Black drama (American) | American drama--Afro-American authors |
Permafrost | Frozen Ground |
Moonshine | Distilling, Illicit |
If you do a subject search in the catalog for books about "permafrost" you will not find any. Why? The authorized Library of Congress subject used in the catalog is not "permafrost" but "frozen ground." If you look up "permafrost" in the Library of Congress Subject Headings, it will say " USE Frozen ground."" USE is the term the Library of Congress uses to direct you from the incorrect subject heading to the correct heading.
Permafrost
USE Frozen ground