The Dewey Decimal Classification System

  • Created by American librarian Melvil Dewey in the 1870s when he was 21 years old
  • the Dewey Decimal Classification (DDC or Dewey, for short) is a system for organising items in a library collection
  • it is the world's most widely used classification system
  • a library classification scheme makes it easier to find what you need on the library's shelves; just as you have a house address, the Dewey number is a book's shelf address
  • At DBIS, the upper primary and secondary NON_FICTION books are arranged according to Dewey numbers

How numbers in DDC are organised

Watch the video Bob the Alien Discovers the Dewey Decimal System.

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


  • 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)

Librarians decide the appropriate Dewey number for a book and attach a "call number" label. The call number is made up of the Dewey number for the subject followed by the first 3 letters of the author's surname.

Using the example above, 599.78 HOS is the call number for the book The Grizzly Bear Family Book by Michio Hoshino.

Last modified: Wednesday, 26 October 2016, 8:45 AM