The Book of the Hidden Agreement (Yinfu jing)
The Yellow Emperor (Huangdi), traditionally ascribed with the authorship of the Book of the Hidden Agreement Despite its brevity, the Yinfu jing (Book of the Hidden Agreement) is one of the most obscure and difficult Taoist texts. Within Neidan (Internal Alchemy), this work is especially well-known for its idea of "stealing the mechanism", which Neidan adepts understand as meaning inverting of the process that leads from the precelestial to the postcelestial domains. Read three sections of the Yinfu jing on the Golden Elixir website. A complete translation of the text, with the commentary by Yu Yan (1258-1314), is found in a chapter or Taoist Internal Alchemy: An Anthology of Neidan texts (Golden Elixir Press, paperback), and in a Kindle ebook, entitled The Book of the Hidden Agreement: A Taoist Text on the Harmony between Heaven and Humanity .