Dewey Decimal System

1. Call Numbers | 2. Dewey Decimal System | 3. Locating a Book

In 1876 Melvil Dewey attempted to organized all human knowledge into 10 big, very general categories. His plan was to find a way to put all the books that covered the same topic together on the library shelves.

Step 1:

He assigned each of these categories a number from 000 to 900. Books were assigned a number for a category based on their subject/s or topic/s.  

Number Category Examples of the Content
 000 General Works Encyclopedias, computers, mysterious events
 100 Philosophy Psychology, parapsychology, witchcraft, dreams
 200 Religion World religions, Christianity, Judaism, mythology
 300 Social Sciences Immigration, social problems, government, folk tales 
 400 Language Foreign languages, origin of language, codes
 500 Pure Sciences Mathematics, biology, chemistry, weather
 600 Technology Medicine, cooking, inventions, flight
 700 Fine Arts Painting, music, dance, games, sports
 800 Literature Poetry, drama, humor, Shakespeare
 900 History and Geography Atlases, world history, countries of the world


Step 2:

Dewey then divided each of these topics in 9 more specific categories. He used a more precise number to identify the smaller categories. This made 100 possible categories. For example: 

General Category 
700 Fine arts 
710 Civic art & landscaping
720 Architecture
730 Sculpture
740 Drawing
750 Painting
760 Graphic arts
770 Photography
780 Music & dance
790 Sports & recreation

Step 3:

Dewey then divided each of these smaller topics into 9 more specific categories. He used an even more precise number to identify the even smaller categories. This made 1000 possible categories. For example:  

Number General Category
 790 Sports & recreation
 791 Public performances
 792 Stage presentations
 793 Indoor games & amusements
 794 Indoor games of skill
 795 Games of chance
 796 Athletic & outdoor sports & games
 797 Aquatic & air sports
 798 Equestrian sports, animal racing
 799 Fishing, hunting, shooting


What Dewey number would you give a book about surfing?

  • Step 1: Surfing is a sport, and sports are in the Fine Arts category which is the 700s.
  • Step 2: Within Fine Arts, the category that fits the best is Sports & Recreation which is 790.
  • Step 3: Within Sports & Recreation, the category that fits the best is Aquatic & Air Sports which is 797. 

So, a book about surfing would be shelved in the 797 section. 

To summarize, all library books are assigned a number based on their topic. Then books are shelved in order by their number. This method is called the Dewey Decimal System, and many libraries use it to organize books. 

Next => Now that you understand how the Dewey Decimal System works, it it is time to learn how to locate a book on the library shelf.  

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