Each item in the library’s collection has a unique call number, which tells where the item is located on the shelves. Stevenson Library uses Library of Congress (LC) Classification, an alpha-numeric system which arranges items by subject so that subject-related items are shelved together and more easily located.

Library materials are shelved alphabetically and numerically depending on the call number, which is determined by the item’s subject. (In the literature section, call numbers are determined by author so that all of an author’s works are shelved together.) Once you identify an item’s call number and collection area (Reference, Main Stacks, Children’s Library, etc.) in the library’s catalog, you can find the item, as well as browse for additional items with similar call numbers. Knowing the letter(s) for your subject area also gives you a place to start when browsing the shelves.

Call numbers appear in two formats (in several lines on the spines of books, and in a single line in the library’s catalog) and are read from top to bottom and left to right, as shown below:

When reading call numbers, consider each line or segment before moving on to the next line or segment. This process is further explained below.

The following table offers explanations and examples of the segments of Library of Congress call numbers. In each row, call numbers are arranged in correct shelf order to show how they would be arranged on the library’s shelves. Bold type indicates the portion of the call number being discussed.

Brief Table of Library of Congress Classification System

Joby Topper
Technical Services Librarian, Stevenson Library, LHUP
Adapted from the Tarleton State University Libraries webpage and The University of Chicago Library webpage, January 2007