6.3 Call Numbers

Library of Congress Classification System

To find an item in the library, you need to know the call number. The call number serves as an intelligent address. It tells you the location of the item and the subject of the item. A call number includes a classification number on the first line and alpha-numeric numbers beneath that.

Most academic libraries in the U.S. use the Library of Congress Classification system to organize their collections. Most public libraries use the Dewey Decimal Classification System. The classification system is a way to shelve items on the same subject in the same area. Please take a quick look at the Library of Congress (LC) Classification Outline. Click some links to subject areas that interest you. The library has the LC Outline posted in several places to help you find books.

When you do research in a particular subject area, you will become familiar with the classification number for the subject. Knowing the classification number for a particular subject is useful for browsing the collection.

How to Read an LC Call Number

Here is the call number of Plants in Hawaiian Medicine by Beatrice H. Krauss.

The first line stands for Hawaiian History. The second line includes the initial of the author's last name and a number. (The letter might also be the first letter in the title or an editor's last name.) The last line is the publication year. 

On the shelf, books are shelved first in alphabetical order according to the letters and numbers on the first line, and then by the letters and numbers on each line below.

The Decimal Point

Notice that there is a period before the author's initial and number. This is a decimal point. It means the numbers on that line are decimal numbers. If two books begin with the same classification number, the smaller decimal number comes first.

Which Comes First?

When two call numbers start with the same numbers on the first line, which comes first?