Subject Searching in AlleyCat
You'd think you could enter any topic as a Subject search in AlleyCat. However, the Subject search uses special terms to organize books by subject. These are called Library of Congress Subject Headings (LCSH for short). If you enter your keywords as a Subject search, you may not get much back. For example:
If you entered a Subject Heading search for: acquired immune deficiency you would get no books!
But if you searched using the LCSH term, AIDS (Disease) you'd see that the library has over 200 books in that broad category, plus numerous others in sub-categories.