Dewey Decimal Classification (DDC) is a classification widely used by libraries all over the world. This classification system was first conceived by Melville Dewey in 1873 and officially published in 1876. Forest Publishing House is responsible for DDC publishing, and 1988 has become a department under OCLC.

DDC has been used by libraries in more than 135 countries around the world and has been translated into more than 30 languages, including Arabic, Chinese, French, Greek, Hebrew, Italian, Persian, Russian, Spanish and Turkish. In the United States, 95% public and school libraries, 25% college and university libraries and 20% professional libraries use DDC. In addition, DDC can also be used to organize various resources on the Internet.