Niagara University Library: Understanding Call Numbers

Niagara University Library
Understanding Call Numbers

(Thanks go to the Library at Honolulu Community College, which granted permission to use this guide.)

Have you ever wondered how library books are assigned their places on the shelves? Did you know that the call number -- the number placed on the spine of the book -- is a code which provides valuable information about the book?

This page will provide an introduction to understanding and using library call numbers.

What are call numbers for?

Each book in the Library has a unique call number. A call number is like an address: it tells us where the book is located in the library.

Call numbers appear

Note that the same call number can be written from top-to-bottom, or left-to-right.

Niagara University Library, like many academic libraries in the U.S., uses Library of Congress Classification for call numbers. This system uses a combination of letters and numbers to arrange materials by subjects.

Reading Call Numbers

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.

What does the call number mean?

Remember that Library of Congress Classification arranges materials by subjects. The first sections of the call number represent the subject of the book. The letter-and-decimal section of the call number often represents the author's last name. And, as you recall, the last section of a call number is often the date of publication.
example:

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. Which letters represent your subject? View the Library of Congress Classification Outline to find out.

Location Prefixes

Many books have call numbers that start with a prefix that provides you with location information on where a book is shelved in the Library.

example:: Ref AG243 .G87 1992

Location prefixes mean that book is shelved in a special place, and may have loan restrictions. The most commonly encountered location prefixes at Niagara University Library are listed below.

Prefix	Collection	Library Location
[Blank]	Circulating Collection	All Three Floors
Ref	Reference Collection	First Floor
Rec.Reading	Recreational Reading Collection	First Floor
Oversize	Oversize -- a big book!	Basement Level
Folio	Books Bigger than Oversize	Basement Level
RBR	Rare Book Room	Second Floor
Reserve	Reserve Book set aside for a class	Circulation Desk
Science Library	Second Floor, DePaul Hall	A Different Building