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Change is a constant

The Dewey Decimal Classification (DDC) system was conceived to accommodate the expansion and evolution of the body of human knowledge. That's why 23 unabridged print editions and 15 abridged editions over nearly 139 years, as well as multiple Web editions since 2000 have been published—to ensure that you have current tools to manage contemporary knowledge organization projects.

The four-volume unabridged edition is published approximately every seven years, reflecting the time the Dewey editorial team needs to implement changes across the entire classification. The 23rd print edition, published in mid-2011, includes many new features that make the classification easier to use. The abridged edition, Abridged Edition 15, published in February 2012, and is well-suited for the classification needs of libraries with up to 20,000 titles in their collections.

WebDewey and Abridged WebDewey, which correspond to the unabridged and abridged print editions, are updated on a regular basis, bringing you ongoing updates implemented by the Dewey editorial team almost as soon as they occur. The Web versions also offer additional electronic functionality not available in the print editions to make your classification work more efficient.

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.

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