Dewey Decimal Classification System

The Dewey Decimal Classification (DDC) system, devised by library pioneer Melvil Dewey in the 1870s and owned by OCLC since 1988, provides a dynamic structure for the organization of library collections. Now in its 22nd edition, and available in print and Web versions, the DDC is the world’s most widely used library classification system. For ordering Dewey, please visit our secure Web store or use the order form.

Benefits

• Provides a logical system for organizing every item in your library’s unique collection
• Offer library users familiarity and consistency of a time-honored classification system used in 200,000 libraries worldwide
• Integrate updates to the DDC almost as soon as they happen through quarterly, electronic updates to WebDewey and Abridged WebDewey

Features

• Classification standards are available in print and Web formats, and full and abridged editions
• The DDC provides meaningful notation in universally recognized Arabic numerals, well-defined categories and hierarchies, and a rich network of relationships among topics
• Teaching tools help librarians, library science students and library users use the DDC efficiently
• Selected ongoing changes to the DDC are posted to the Dewey Web site regularly

Requirements

• The electronic versions of the DDC, WebDewey and Abridged WebDewey, require a minimum hardware configuration

Recent enhancements

• The four-volume print edition of DDC 22 was published in July 2003. It provides many new and updated numbers and topics, as well as tools to enhance classifier efficiency, all without major revisions to the schedules
• The first electronic versions of DDC 22 became available in WebDewey on June 15, 2003

Web resources

• New Dewey numbers and LCSH mappings
• Classification research at OCLC
• Educational resources for new librarians and new Dewey users

Related services

• WebDewey and Abridged WebDewey are available as add-on services to OCLC Connexion, OCLC’s flagship cataloging service

All copyright rights in the Dewey Decimal Classification system are owned by OCLC.
Dewey, Dewey Decimal Classification, DDC, OCLC and WebDewey are registered trademarks of OCLC.