In the Dewey Decimal System, each number stands for a special topic or subject.

  • Every book or item in a library is given a number and is put on the shelf in number order.

  • Books with the same number which are about the same topic/subject are grouped together on the library shelves.

Here are three tables for the Dewey Decimal System. 

1. In the first, Dewey divided knowledge into 10 main subject areas like this:

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

2. In the second table Dewey divided each of the 100s into 10s like this example using the 500s


510 Mathematics
520 Astronomy
530 Physics
540 Chemistry
550 Earth Sciences
560 Paleontology
570 Life Sciences
580 Botanical Sciences
590 Zoological Sciences

Then Dewey did it again!

3. In the third, Dewey divided each of the numbers again into 10 smaller numbers. Each time he was making the subjects/topics more and more specific.

Here's how Dewey divided the 590s which are all about animals

590 Animals for books with general information about lots of animals

591 Natural history of animals

592 Invertebrates: animals without a backbone such as worms

593 Marine and seashore invertebrates such as corals

594 Molluscs such as animals with shells: snails and octopus

595 Arthropods such as insects, spiders and centipedes

596 Vertebrates

597 Cold blooded vertebrates such as reptiles and fish, frogs and toads

598 Birds

599 Mammals of land and ocean