The Dewey Decimal Classification (DDC), colloquially known as the Dewey Decimal System, is a proprietary library classification system that allows new books to be added to a library in their appropriate location based on subject. It was first published in the United States by Melvil Dewey in 1876. Originally described in a forty-four-page pamphlet, it has been expanded to multiple volumes and revised through 23 major editions, the latest printed in 2011. It is also available in an abridged version suitable for smaller libraries. OCLC, a non-profit cooperative that serves libraries, currently maintains the system and licenses online access to WebDewey, a continuously updated version for catalogers.

Source: Wikipedia