The Dewey Decimal Classification (DDC) system helps to organize (classify) non-fiction books in the library by organizing information into 10 categories, which are called "classes". You can organize books generally into these 10 main classes, or you can organize information more specifically depending on how detailed the book's subject is. When you sort information categorically under the 10 main classes, it is called a "hierarchy". The DDC displays this hierarchy of information using numbers.

The 10 Classes

How did Melvil Dewey come up with his classification system?

Dewey Decimal Call Number	Books About	What Question Do These Books Answer?	Example (with call number)
000	Computer science, information &  general works	How do we organize information?	Guinness Book of World Records
100	Philosophy & psychology	Who am I?
200	Religion	How did we get here?
300	Social sciences	Who are the people in the world?
400	Language	How can I communicate with others?
500	Science (and math)	How can I explain the world around me?
600	Technology (applied sciences)	How can I control the world around me?
700	Arts & recreation	How can I enjoy my free time?
800	Literature	What are the stories of our lives?
900	History & geography	What was the world like in the past?

Each of the 10 classes can be further divided into 10 divisions (100 divisions total), and each division can be divided into 10 sections (1000 sections total). Click here to see the classes, divisions, and sections, and how the hierarchy of information looks.

So, what does this mean to you? When you're looking for a book in the library, or when the OPAC computer gives you a call number, where do you go? For example, animals are a very popular topic at the Robinson Library. Let's break down the Science class (the 500s) to the 590 division and see how Animals are classified:


If a student is looking for a book about koalas, the Dewey Decimal number breaks down like this:




Links

• a multimedia tour of the DDC by OCLC
• The basics of how the DDC works
• "Do We" Really Know Dewey?: created by 5th & 6th graders in Arkansas
• Doin' Dewey with Mr. B
• a simple explanation of the DDC from the Brooklyn Children's Museum & and the Brookly Public Library