The H-FARM Library adopted the Dewey Decimal Classification (DDC), which is a system that allows libraries to classify their books in order of subject. It was invented by Melvil Dewey in 1876 and is periodically updated by OCLC (Online Computer Library Center).
The Dewey Decimal Code is a numeral shelf mark which follows precise rules, which can be found in OCLC's website: Introduction to DDC and DDC Summaries.
If you don't know how to put a book back in its place, ask the librarian!
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