De Occulta Philosophia (Three Books of Occult Philosophy)

Cornelius Agrippa · 1533

A Renaissance compendium of magic and numerology that systematized the correspondences between numbers and letters.

He gathered into one volume the Kabbalistic, Pythagorean and Hermetic tradition of numbers, fixing the correspondences that Western numerology took up centuries later.

Agrippa codified the number-letter correspondence tables that modern numerology later used. It's at once a brilliant synthesis and a work with no empirical basis.