Refresher on Dewey Decimal System

Because of the scheduled computer down time last week, I had some time to reflect on how dependent I am upon computers, even for something as simple as figuring out where a book is in the nonfiction section. Sure, I know the Dewey Decimal System, but I don’t trust my knowledge. I always double guess myself, and pass it off as “making sure our book is available.” So I figure that now is a good time for a refresher on the Dewey Decimal Classification system.

History & Explanation

The Dewey Decimal Classification (DDC) system was devised by Melvil Dewey and patented in 1876. It began as a short 42 page guide to classification, and has since grown to over 4,037 pages. It is frequently updated to reflect current subjects.

The DDC organizes information by subject rather than alphabetically by title or author. There are ten major areas of subjects, and ten divisions of each subject. Within each subdivision, there are countless variations. Subjects are assigned numbers; each number means something specific.

Dewey Decimal Subject Divisions

000 Generalities
100 Philosophy & Psychology
200 Religion
300 Social Sciences
400 Language
500 Natural Sciences & Mathematics
600 Technology (Applied Sciences)
700 The Arts
800 Literature & Rhetoric
900 Geography & History

How to Read a Call Number

Example: 142.780973     Existential America by George Cotkin

100 Philosophy & Psychology
140 Specific philosophic schools
142 Critical philosophy
142.7 Phenomology
142.78 Existentialism
142.780973 About existentialism in America

There are sometimes letters and numbers following the Dewey Decimal number. When these show up, don’t be alarmed. It’s just another way of making the book unique and easy to find. They indicate the author and publication date, as well as other assorted things.

When shelving books, you should first shelve by the numbers before the decimal point. Then, once you’re in the right area, shelve the book by the numbers following the decimal point. That is, shelve in the following order (example):

The Comforts of Country
Antiques of the Future by Lisa S. Roberts
Creating the Look: Swedish Style by Katrin Cargill
Two Hour Garden Art by Ruby Begonia

When in Doubt

And when in doubt, here are some great websites that you can use to study the classifications or to use when/if our card catalog is down.

University of IL-Urbana Champaign, “A Guide to Call Numbers”

Middletown Thrall Public Library, “Do the Dewey! Trivia Game”

Appleton Public Library, “Alphabetical Dewey Decimal Guide to Common Topics”


About shortlibrarian

I am a woman working in the Twin Cities as a programming Librarian.
This entry was posted in Tips for Reference and tagged , , , , , , . Bookmark the permalink.

1 Response to Refresher on Dewey Decimal System

  1. Ariel Price says:

    Fascinating! I’m not a librarian, but I love the library and the Dewey Decimal system has always mystified me. Thanks for the explanation!

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