The Three Books of Occult Philosophy (De Occulta Philosophia libri III) was written in the 16th century by Henry Cornelius Agrippa's. It involves the study of occult philosophy, the powers of ritual magic and its relationship with religion. This version of Book I was originally published in 1898 and Edited by Willis F Whitehead. It involves the study of Natural Magic, the nature of the four elements, The Planets, Celestial signs, geomancy, amongst others.