The Dewey Decimal Classification (DDC) system was devised by Melvil Dewey in the 1870s. Since 1988 it has been owned by OCLC. The system provides a dynamic structure for the organisation 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. The website provides news about DDC, details of translations, online DDC catalogues, research, editorial policy and Dewey licensing. There are sections on updates, discussion, educational resources, ordering and support. PDF versions of DDC22 highlights may be downloaded.