Dewey Decimal System

Understanding the Dewey Decimal System
With thousands of books in a library, a system was needed to make it as easy as possible for a person to find what they needed. A librarian named Melville Dewey devised a system that is in use by most small libraries around the world.
The system uses numbers. The numbers have meaning, so those books about the same topic are grouped together. Each book has three digits. After the third digit, a decimal point is used and as many digits as necessary can be added after the decimal point.
If you know the Dewey number of the topic you are researching, you know that all other books on that topic have the same Dewey number and will be located together in the library.
Ten Main Classes
  • 000  Generalities:   Encyclopedias, almanacs, unusual phenomena
  • 100  Philosophy & Psychology:   Books that try to explain our ideas and thoughts
  • 200  Religion:   Books about our beliefs
  • 300  Social Sciences:   Books about cultures, education, problems
  • 400  Language:   Books about different languages, dictionaries
  • 500  Natural Sciences & Mathematics:   Chemistry, physics, astronomy, biology, geology
  • 600  Technology (Applied Sciences):   Medicine, engineering, agriculture, manufacturing
  • 700  The Arts:   Painting, drawing, architecture, music, recreation
  • 800  Literature:   Drama, poetry, speeches, humor
  • 900  History:   History, geography, travel books, biographies

There are two important numbers that you should know. Much of the work we do in school is about people. A book about more than one person is a collective biography. Collective biographies are classified as 920. A book about only one person is an individual biography. Individual biographies are classified as 921.
The Call Number
A Book's Address in the Library
Call numbers are on the spine of the book, on the bar code label, and on the book pocket. The call number is the book's address in the library. It tells you where the book can be found. Following is a brief overview of what the call number contains.
Nonfiction are books that inform the reader. The author must present facts without distorting the truth. Nonfiction call numbers are the Dewey classification number, and then the first three letters of the author's last name. These call numbers put all the books about the same subject together, in alphabetical order by the author's last name.

Individual Biography (921)
The call number for an individual biography uses the Dewey number 921 and the first three letters of the last name of the person who the book is written about. All books about the same person are grouped together. Books are shelved in alphabetical order, making it easier to find a book about a specific person.

Collective Biography (920)
A collective biography is about more than one person. The call number uses the Dewey number for collective biography, 920, and then the first three letters of the author's last name.

Reference Books (REF)
Reference books provide extensive information on one or several subjects. These books usually don't leave the library. Some are checked out for one day. The call numbers of reference books have a first line of "R" or "REF," the Dewey number for the subject covered, then the first three letters of the author's last name, or the first three letters of the title if the author is not identified.
Fiction books are books whose purpose is to entertain the reader. They are the product of the author's imagination. While there may be factual events or persons in the story, a fiction book is not meant to be a resource of information. For fiction, the call number is "Fic” or “FIC” and then the first three letters of the author's last name. Even though it is made up of letters, we still call it a call number.

Story Collections (SC)
Story collections are collections of short stories and are shelved before the fiction books.