Dewey Decimal System

A Guide to the Dewey Decimal System

By The Cumudgeony Librarian

In today’s library finding books that you want to read is tricky, but not impossible. Back in the old days the library looked nothing like it does now. Back then books were in what were called “closed stacks.” This meant that the books were behind a counter and the library users-or patrons-had to ask the library staff to go and fetch all the books they wanted to see. This was time consuming and hard for both staff and patrons. After all, the patrons would have to know exactly which books they were looking for, not to mention the loss of privacy in having to share with the librarian what you were interested in reading.

Then in the 1860s there was an explosion in the number of libraries in the United States. Libraries began to spring up everywhere. People flocked to the library in never before seen numbers. The Librarians were overjoyed at this sudden growth, but face with a problem of not enough staff to get the books quickly enough for all these new patrons. Libraries decided to change over to something called “Open Stacks” to help all the new patrons. The patrons could browse the stacks looking and searching themselves.

But there was a problem, before open stacks the books were organized by something called “shelf order.” This meant that the books were organized by when they came in, so a book on cats could be stuck right next to one on mathematics and another on the biography of John Stuart Mill. This would be confusing to patrons and take up more of their time. This was a Bad Thing. One of our most basic rules is “whenever possible save the time of the patron.”

This being the case, shelf order had to go. Some parts of fixing this problem were easy. Fiction books could be shelved alphabetically by author’s last name. Biographies could be shelved alphabetically by the subject’s name as well.

As nice as this was, it still left the sticky problem of the non-fiction collection. How does one organize non-fiction so that people don’t have to spend hours looking for titles?

Many librarians had wrestled with this problem, but in 1876 Melvil Dewey, an early library pioneer came up with a system for classifying books and other materials by subject matter. Dewey’s work built on the past work such as Charles A.Cutter, but the key point of Dewey’s work was that it was flexible. First published in the late 19th century, it is still in use and has been revised many times. Currently it is in its 22nd revision with the publication of the DDC 22 in
July of 2003.

While the most commonly used system in US public libraries, Dewey’s Decimal system isn’t the only system out there. The Library of Congress Classification(LCC) is used in most research and university libraries. The Universal Decimal Classification (UDC) is an elaboration of the Dewey system and is used in specialized libraries such as music libraries or document archives. The Colon Classification (CC) has proved particularly popular in India and in many parts of the world.

So, how does the Dewey System work? The Decimal System is based on the number ten. Subjects are divided into ten main groups that are represented by a series of numbers: from 000 to 900.

000 General works (including encyclopedias and general
100 Philosophy and psychology
200 Religion
300 Social sciences
400 Languages
500 Sciences
600 Applied sciences / Technology
700 The Arts
800 Literature
900 Geography, history and travel

Each of these ten groups of 000 to 900 is then further divided down into more specialized subject fields, again represented numerically, for example:

600 Technology700 The Arts
630 Agriculture740 Drawing & decorative arts
636 Animal husbandry (pets)741.5 Cartooning

For more information there is also an Alphabetical Guide to Common Subject Headings, which has dewey numbers for the more commonly used subjects.

The Dewey Decimal Classification is © 1996-2003 OCLC Online Computer Library Center, Inc.
DDC, Dewey, and Dewey Decimal Classification are registered trademarks of OCLC Online Computer Library Center, Inc.

Dewey Decimal Classification System


General works
(including encyclopedias and general reference)


Philosophy and

000 Generalities100 Philosophy and Psychology
010 Bibliography110 Metaphysics
020 Library & information sciences120 Epistemology, causation, humankind
030 General encyclopedic works130 Paranormal phenomena
040 Unassigned140 Specific philosophical schools
050 General serials & their indexes150 Psychology
060 General organizations & museology160 Logic
070 News media, journalism, publishing170 Ethics (moral philosophy)
080 General collections180 Ancient,medieval, Oriental philosophy
090 Manuscripts & rare books190 Modern Western philosophy




Social sciences

200 Religion300 Sociology and anthropology
210 Natural theology310 General statistics
220 Bible320 Political science
230 Christian theology330 Economics
240 Christian moral & devotional theology340 Law
250 Christian orders & local church350 Public administration
260 Christian social theology360 Social services; associations
270 Christian church history370 Education
280 Christian denominations & sects380 Commerce, communications, transport
290 Other & comparative religions390 Customs, etiquette, folklore





400 Language500 Natural sciences & mathematics
410 Linguistics510 Mathematics
420 English & Old English520 Astronomy & allied sciences
430 Germanic languages German530 Physics
440 Romance languages French540 Chemistry & allied sciences
450 Italian, Romanian languages550 Earth sciences
460 Spanish & Portuguese languages560 Paleontology, paleozoology
470 ltalic languages, Latin570 Life sciences
480 Hellenic languages, Classical Greek580 Botanical sciences
490 Other languages590 Zoological sciences


Applied sciences /


The Arts

600 General technology700 The Arts
610 Medical sciences and medicine710 Civic & landscape art
620 Engineering & allied operations720 Architecture
630 Agriculture730 Plastic arts, sculpture
640 Home economics & family living740 Drawing & decorative arts
650 Management & auxiliary services750 Painting & paintings (museums)
660 Chemical engineering760 Graphic arts, printmaking, prints, postage stamps
670 Manufacturing770 Photography & photographs
680 Manufacture for specific uses780 Music
690 Buildings790 Recreational & performing arts




Geography, history and

800 Literature & rhetoric900 World History
810 American literature910 Geography and travel
820 English & Old English literatures920 Biography, genealogy, insignia
830 Literatures of Germanic languages930 History of the ancient world
840 Literatures of Romance languages940 General history of Europe
850 Italian, Romanian literatures950 General history of Asia, Far East
860 Spanish & Portuguese literatures960 General history of Africa
870 Italic literatures, Latin970 General history of North America
880 Hellenic literatures, Classical Greek980 General history of South America
890 Literatures of other languages990 General history of other areas

All copyright rights in the Dewey Decimal Classification system are owned by OCLC.
Dewey, Dewey Decimal Classification, DDC, OCLC and WebDewey are registered trademarks of OCLC.

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