History of the Dewey Decimal Classification System

• The DDC system is used in most of the world's libraries.Creatas Images/Creatas/Getty Images
  
  Since Melvil Dewey's creation of the DDC system in the 1870s, it has been constantly revised. The DDC system has been through 22 unabridged print editions and 14 abridged editions since it was first published in 1876. In 1988, the Online Computer Library Center, Inc. (OCLC) took ownership of the DDC and has made it into the world's most widely used library classification system. The print edition of DDC 22 (the latest edition) was published in July 2003. The electronic version of DDC 22, the first online edition, also became available that year.
  
  

Overview of the DDC System

• The Dewey Decimal Classification system is made up of 10 classes. Each class has 10 divisions, with each of those having 10 sections. The numbers range from 000.000 to 999.999. Not every number in every section is used; some haven't been allocated yet, and others have been abandoned over time. When two books have the same DDC system number, the second line consists of letters, typically the first few letters of the author's last name. Books are shelved in increasing numerical order first and then in alphabetical order, according to the second line.
  
  

Main Classes of the DDC System

• These are the 10 main classes of the DDC system:
  
  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
  
  

Fiction in the DDC System

• Fiction books are often cataloged apart from nonfiction books.Jupiterimages/BananaStock/Getty Images
  
  While the DDC system is considered mainly to be used for nonfiction books, American fiction, for example, is technically classified at 813 under the Literature class. But since that one number could potentially take up the majority of a library's books, most libraries opt to keep the fiction and nonfiction books separate. Instead of using DDC system numbers, library patrons search for fiction books by the alphabetical order of the author's last name.
  
  

How Books Are Assigned a DDC System Number

• The Library of Congress plays a role in assigning DDC system numbers.Comstock/Comstock/Getty Images
  
  The OCLC acquired all trademark and copyrights associated with the DDC system in 1988. Work done by the OCLC editorial staff is reviewed by the Decimal Classification Editorial Policy Committee (EPC), a 10-member international board.
  
  Each newly published book is assigned a DDC system number by a division of the Library of Congress. The number selection is then either accepted or rejected by the OCLC advisory board. Almost 100 percent of the recommended numbers are accepted.