The Dewey Decimal Classification system is named after Melvin Dewey, who created it in 1873. This system is widely used in public libraries, but in a few exceptions is also used in academic libraries.
Dewey Decimal serves to organize library materials by their general knowledge field. Every DDC number contains three digits, similar to a MARC tag, but rather than describing the item itself, the DDC number describes what the item is generally about. The first number of the DDC tag represents its broad general field--is it about religion or geography?--while the second and third numbers represent more specific topics.
