For what is the Tiaou? The frequent allusion to it in the _Book of the Dead_ contains a mystery. Tiaou is the path of the Night‐Sun, the inferior hemisphere, or the infernal region of the Egyptians, placed by them on the _concealed side of the Moon_. The human being, in their Esotericism, came out from the Moon—a triple mystery, astronomical, physiological and psychical, at once; he crossed the whole cycle of existence, and then returned to his birth‐place, before issuing from it again. Thus the Defunct is shown arriving in the West, receiving his judgment before Osiris, resurrecting as the God Horus, and circling round the sidereal heavens, which is an allegorical assimilation to Ra, the Sun; then having crossed the Noot, the Celestial Abyss, returning once more to Tiaou; an assimilation to Osiris, who, as the God of life and reproduction, inhabits the Moon. Plutarch(360) shows the Egyptians celebrating a festival called “The Ingress of Osiris into the Moon.” In the _Ritual_,(361) life is promised after death; and the renovation of life is placed under the patronage of Osiris‐Lunus, because the Moon was the symbol of life‐ renewals or reïncarnations, owing to its growth, waning, dying, and reäppearance every month. In the _Dankmoe_,(362) it is said: “O Osiris‐ Lunus, that renews to thee thy renewal.” And Sabekh says to Seti I:(363) “Thou renewest thyself as the God Lunus, when a babe.” It is still better explained in a Louvre papyrus:(364) “Couplings and conceptions abound when he [Osiris‐Lunus] is seen in heaven on that day.” Says Osiris: “O sole radiant beam of the Moon! I issue from the circulating multitudes [of stars].... Open me the Tiaou, for Osiris N. I will issue by day to do what I have to do amongst the living”(365)—_i.e._, to produce conceptions. Osiris was “God manifest in generation,” because the ancients knew, far better than the moderns, the real occult influences of the lunar body upon the mysteries of conception. In the oldest systems we find the Moon always male. Thus Soma, with the Hindûs, is a kind of sidereal Don Juan, a “King,” and the father, albeit illegitimate, of Budha—Wisdom. This relates to Occult Knowledge, a wisdom gathered through a thorough acquaintance with lunar mysteries, including those of sexual generation. And later, when the Moon became connected with the female Goddesses, with Diana, Isis, Artemis, Juno, etc., this connection was also due to a thorough knowledge of physiology and female nature, physical as much as psychic.