Dewey Decimal Classification

The Dewey Decimal Classification (DDC; DOO-ee, DYOO-ee), colloquially known as the Dewey Decimal System, is a proprietary library classification system which organizes books based on discipline and subject. It was first published in the United States by Melvil Dewey in 1876.

Source: Wikipedia — Dewey Decimal Classification (CC BY-SA 4.0)