Subject headings are a set of controlled vocabulary used to classify materials. Most library catalogs and databases include subject headings (sometimes called descriptors or keywords). You can use subject headings to improve the exactness and effectiveness of your searching.

A controlled vocabulary is a restricted set of words used to describe things. The conservation directory, for example, uses a controlled vocabulary to help you find listings (i.e., National Parks, BLM, and Indian Affairs are all listed under the same heading, allowing you to more easily find all of them together).

Likewise, book records in the library catalog have subject headings that describe the key topics of the books. Real subject headings include:

    * Energy conservation
    * United State, Dept. of Energy
    * Water supply - West
    * Conservation biology
    * Wildlife conservation

Finding subject headings that match your topic is a good way of locating library materials. Search the library Using “Subject Headings” in the Merrill-Cazier online catalog for an introduction to finding and searching with subject headings in the library catalog.