The El Libro de los Misterios.

The Libro de los Misterios (The Book of Mysteries) is a book on demonology, spirituality, and history written by Spanish monk Antonio Ferdinand Cortes, who was burned at the stake in 1646.  The Libro de los Misterios was found in the Spanish fort town of Irun by French, who then tried to burn the Book, but could not, so they buried the cursed Book.  El Libro de los Misterios turned up in the hands of the Madrid Occult who hid the book away in their library.  The Libro de Misterios tells history from a truthful viewpoint, Antonio Cortes was said to have traveled to the Astral Plane before he wrote the Book, a vast collection of demonological topics and witchcraft.  It has some pages all over the that talk of other dimensions and mystical beings from these dimensions.