Manly Hall

Manly Palmer Hall (March 18, 1901 - August 29, 1990) was a prolific American author and mystic. He is perhaps most famous for his work The Secret Teaching of All Ages: An Encyclopedic Outline of Masonic, Hermetic, Qabbalistic and Rosicrucian Symbolical Philosophy, which he published at the age of twenty five; the first line of which is, "Philosophy is the science of estimating values."