The Book of Enoch the Prophet
Translated by Richard Laurence
The book of Enoch is one of the strangest of the books left out of the Biblical canon. Filled with goetic angels and demons, and visions of inconceivable lands beyond the sky, writers have tied Enoch into everything from archaeoastronomy, Astrology, Alchemy, the Kabbalah, and Gnosticism. In the middle of this is what appears (to me, at least) to be an operations manual for a Neolithic observatory, with rules for when to look for various celestial bodies through 'gates.'