The Secret Teachings of All Ages (1928) by Manly P. Hall is an extensive, illustrated encyclopedia exploring Western esoteric traditions, including Hermeticism, Kabbalah, alchemy, and Freemasonry. It interprets ancient myths, symbols, and occult philosophies as a unified, hidden "perennial wisdom" meant to guide spiritual seekers toward understanding their divine origin. Hall’s masterpiece is regarded as a comprehensive reference guide to mystical and esoteric studies, aiming to preserve the hidden insights of sages and initiates.