The Dewey Decimal System

Ah yes, that old elementary school lesson...

Who was Dewey? And what did he do?

Melvil Dewey created a system for organizing books based on grouping topics. Nearly all public K-12 libraries and nearly a quarter of all college and special libraries use the Dewey Decimal System, sometimes called the DDC (Dewey Decimal Classification.) The books are labelled with a three number code to define the exact topic, with decimals to distinguish subtopics. Groups of books are classified using the first number in the code (for example, 800s are Literature and Rhetoric, and 500s are Natural Sciences and Math)