The Dewey Decimal Classification

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Devised by American librarian Melvil Dewey in the 1870s when he was 21 years old and working as an assistant in a college library, the Dewey Decimal Classification (DDC) is a system for organizing items in a library collection. It is the world's most widely used classification system and is used in over 200,000 libraries worldwide, including 95% of public and K-12 school libraries and 25% of college and university libraries. At CSU, it is used to organize the curriculum materials collection and the children's literature collection.

The purpose of a library classification scheme is to make it possible for users to easily find what they need on the library's shelves. It is similar to the concept in the non-library world of street names and house numbers which makes it possible to locate residences and businesses. The DDC is based on the concept that items on the same subject should be placed together for ease of reference, and it provides a logical system organized by subjects that covers the entire world of knowledge. It divides this world of knowledge into ten main classes, 100 divisions, and 1,000 sections.

The 10 main classes:

000 Computer science, information & general works
100 Philosophy & psychology
200 Religion
300 Social sciences
400 Language
500 Science
600 Technology
700 Arts & recreation
800 Literature
900 History & geography

 

The 100 main divisions:

  • 000 Generalities
  • 010 Bibliography
  • 020 Library & information science
  • 030 General encyclopedias
  • 040 Not used
  • 050 General serial publications
  • 060 Organizations
  • 070 Journalism, publishing, media
  • 080 General collections
  • 090 Manuscripts & rare books
  • 100 Philosophy & Psychology
  • 110 Metaphysics
  • 120 Epistemology, causation, humankind
  • 130 Paranormal phenomenon
  • 140 Specific philosophical schools
  • 150 Psychology
  • 160 Logic
  • 170 Ethics
  • 180 Ancient, medieval, Oriental philosophy
  • 190 Modern western philosophy
  • 200 Religion
  • 210 Philosophy & theory of religion
  • 220 Bible
  • 230 Christianity
  • 240 Christian moral & devotional theology
  • 250 Christian orders & local church
  • 260 Social & ecclesiastical theology
  • 270 History of Christianity & Christian sects
  • 280 Christian denominations
  • 290 Comparative religion & other religions
  • 300 Social Sciences
  • 310 Statistics
  • 320 Political science
  • 330 Economics
  • 340 Law
  • 350 Public administration & military science
  • 360 Social programs & services
  • 370 Education
  • 380 Commerce
  • 390 Customs, etiquette, folklore
  • 400 Language
  • 410 Linguisitics
  • 420 English & Old English
  • 430 Germanic
  • 440 French
  • 450 Italian, Romanian, Rhaeto-Romanic
  • 460 Spanish & Portuguese
  • 470 Latin
  • 480 Greek
  • 490 Other languages
  • 500 Natural Sciences & Math
  • 510 Math
  • 520 Astronomy
  • 530 Physics
  • 540 Chemistry
  • 550 Earth sciences
  • 560 Paleontology
  • 570 Life sciences
  • 580 Plants
  • 590 Animals
  • 600 Technology & Applied Sciences
  • 610 Medicine
  • 620 Engineering
  • 630 Agriculture
  • 640 Home economics (cooking)
  • 650 Management
  • 660 Chemical engineering
  • 670 Manufacturing
  • 680 Manufacture for specific uses
  • 690 Building
  • 700 Arts, Sports, Recreation
  • 710 Civic & landscape art
  • 720 Architecture
  • 730 Plastic arts (sculpture)
  • 740 Drawing & decorative art
  • 750 Painting
  • 760 Graphic arts
  • 770 Photography
  • 780 Music
  • 790 Recreation, performing arts, sports
  • 800 Literature & Rhetoric
  • 810 American
  • 820 English & Old English
  • 830 Germanic
  • 840 French
  • 850 Italian, Romanian
  • 860 Spanish, Portuguese
  • 870 Latin
  • 880 Greek
  • 890 Other literatures
  • 900 Geography, History, Biography
  • 910 Geography, travel
  • 920 Biography, genealogy, insignia
  • 930 Ancient world
  • 940 Europe
  • 950 Asia
  • 960 Africa
  • 970 North America
  • 980 South America
  • 990 Other areas

 


Creating numbers in DDC

The smallest numbers (only three digits long) are used to identify materials with broad subjects; larger numbers (created by adding digits after a decimal point) are used to describe narrower subjects. The use of numbers after the decimal point is what gives this system its name, its flexibility, and its usefulness in classifying a wide range of subject material.

Example:

  • 500 Science (one of the 10 main classes)
    • 590 Animals (one of the 100 divisions)
      • 599 Mammals (one of the 1,000 sections)
        • 599.7 Carnivores (a specific kind of mammal)
          • 599.78 Bears (a specific kind of carnivore)
            • 599.785 American black bear (a specific kind of bear)

Librarians determine appropriate Dewey numbers and mark each item in the library's collection with a "call number" which consists of the Dewey number for the subject matter and another number (called a Cutter number) that places the author or title of the book in alphabetical order. The items are then placed on the shelves in order by their Dewey numbers and then by their Cutter numbers. Occasionally a year will be added to the call number.

Examples of books in order on the shelves (reading from left to right) by their Dewey numbers and Cutter numbers:

(Dewey) 331 331.133 331.133 331.31 331.481385 331.8
(Cutter) L573 H242 L773 S273 L665 P889


Further information

For a very thorough explanation of the DDC and how it works, a tutorial, "Dewey to the Rescue," provides a tour of the DDC and is available at http://www.oclc.org/dewey/resources/tour/default.htm

On that page choose "Take the multimedia tour."

(Note: A Macromedia Flash Player Plugin (available here) is required for viewing).