Universal Decimal Classification Apr 2026

Using numbers that any person, regardless of language, could understand.

Able to cover every field of knowledge, from Philosophy to Engineering. universal decimal classification

To make this work, they needed a classification system that was: Using numbers that any person, regardless of language,

Otlet and La Fontaine didn't just want a library; they wanted a "city of knowledge". In 1895, they founded the Mundaneum in Mons, Belgium—a pre-digital precursor to Google. In 1895, they founded the Mundaneum in Mons,

Using symbols like colons (:) or pluses (+) to show how different subjects—like Physics and Medicine —linked together to form new ideas like Biophysics . The System: A Mathematical Map of Mind

In the late 19th century, two Belgian visionaries, and Henri La Fontaine , looked at the world’s exploding volume of information and saw a looming "Pit of Despair"—a future where human knowledge would be lost simply because it couldn't be found.

The UDC divides all human knowledge into ten main "houses" (classes), numbered 0 to 9: