Using LC Subject Headings
The field labled Subject Term (under the catalog record tab of your item record). for a library catalog record contains one or more Library of Congress (LC) Subject Headings. Most libraries use these headings as a way to control the use of words to represent specific concepts. Our search just happened to use the same words used by the library catalogers: Endangered Species. Another LC Subject Heading applied to this particular book is Wildlife Conservation. Clicking on either of the subject headings, creates an alphabetical list of subject headings around the one you selected.
This example shows a few of the entries around "Endangered Species United States," which was the heading given to our book. The number of titles we have for each subject heading is listed after the heading.
A Subject Heading search with the words "wildlife conservation" or "endangered species" will find books with a more general focus on these topics.