Dewey Decimal Classification: 2025 (4 Volumes Set)

The Dewey Decimal Classification (DDC) system is a general knowledge organization tool that is continuously revised to keep pace with knowledge. The system was conceived by Melvil Dewey in 1873 and first published in 1876. The DDC is published by OCLC Online Computer Library Center, Inc. OCLC owns all copyright rights in the Dewey Decimal Classification, and licenses the system for a variety of uses. The DDC is the most widely used classification system in the world. Libraries in more than 140 countries use the DDC to organize and provide access to their collections, and DDC numbers are featured in the national bibliographies of more than 60 countries. Libraries of every type apply Dewey numbers on a daily basis and share these numbers through a variety of means (including WorldCat, the OCLC Online Union Catalog). Dewey is also used for other purposes, e.g., as a browsing mechanism for resources on the web.

The Dewey system’s numerical classification provides a shorthand identification and location tool. The notation lends itself to memory through the constant repetition of a standard pattern (area arrangement, different numbers for particular languages), through parallel subject developments (each book of the Bible given the same development as the Bible as a whole), and through patterned repetition of standard subdivisions (theory, study and teaching, history, geography, etc.). To distinguish works within a group and to expedite retrieval, many libraries add a book number created from the Cutter, or Cutter-Sanborn, Tables, which provide further specifications for author and genre.

Because an abridged as well as a full schedule (or classificatory guide) of the system has been developed, the Dewey Decimal Classification is adaptable to libraries of various sizes. The Index to the Dewey Decimal systems, a relative one (i.e., one having cross-references), arranges all topics expressed or implied, with every synonym in alphabetical order.

The names Dewey Decimal Classification and Dewey (when referring to the former) are trademarks of the OCLC Online Computer Library Center.