Understanding Call Numbers and Locating Materials in the Library

Call Numbers

The Goodwin Library organizes its collections by subject. These subjects are represented by a call number system called the Library of Congress Classification System (LC). LC uses call numbers that begin with letters.

If you were looking for the book The Legend of Cessna by Jeffrey L. Rodengen using the online catalog you would find that the call number is TL686.C4 R63 2007. But what does this number mean?


The first section can be one to three letters. It represents the subject of the book. TL items are about technology, specifically motor vehicles and aeronautics.

686. C4

The second section describes the subject in more detail (in this case - airplanes)


The third section describes the author.

The R stands for the author's last name(Rodengen)


The book was published in 2007

Putting Call Numbers in Shelf Order

To understand how call numbers are put in order in Library of Congress Classification, again look at each section of the call number.

Why is this important to know?

Because books are classified by subject, you can often find several helpful books on the same shelf, or nearby. For example, within the same call number LB2395, there are other guides for college study. Since Library of Congress Classification arranges materials by subjects, knowing the letter(s) for your subject area gives you a place to start browsing the shelves.

Goodwin Library's Special Call Number Prefixes

Library of Congress begins all their call numbers with letters from A to Z. Note: In the Library of Congress system, "P" is for literature. Fiction books can be found in the "P" section.

Goodwin Library also uses prefixes for special collections stored in special locations.

Reserved items on the Reserved Shelf behind the circulation desk is the only special collection that does not use a prefix in front of its call numbers. These items move to and from the Reserved Shelf depending on need. Look in the item type and location fields of the catalog record to identify Reserved items.