Dewey Decimal System

A typical library contains thousands of books. Without some system of organization, we'd never be able to locate any of the books that we need. Classification systems are designed to provide a clear way to find books in specific sections of the library.

Most public libraries use the Dewey Decimal System, which was introduced by Melvil Dewey in 1873. When you become familiar with this system, you'll be able to find books easily in most any public or grade school library.

Note: Colleges use a different system, called the Library of Congress Classification System.

At the very base of the Dewey Decimal system is a set of ten categories or classes. Each broad class has been assigned a number section. The number classes are:

• 000 - Encyclopedias, journals, news, and general collections
• 100 - Philosophy, psychology, paranormal
• 200 - Religion, churches
• 300 - Social sciences, law, etiquette, customs
• 400 - Languages from around the world
• 500 - Math and science
• 600 - Applied Sciences, medicine, engineering, farming, manufacturing
• 700 - Architecture, art, photography, music
• 800 - Literature
• 900 - History, geography

Within each of these main classes, book topics are divided into smaller sub-topics with numbers that fall within the class. For example, the history & geography class would contain:

• 910 - Travel
• 920 - Biography
• 930 - Ancient world

You'll see that your library books have long, complex codes on the back. The first part of this code is the classification number.

Below you'll find a list of many topics you might cover in your school research.

Topics and Classifications