. . . The Book of Eibon, that strangest and rarest of occult forgotten volumes ... is said to have come down through a series of manifold translations from a prehistoric original written in the lost language of Hyperborea.
—Clark Ashton Smith, "Ubbo-Sathla"

The Book of Eibon, or Liber Ivonis or Livre d'Eibon, is attributed to Clark Ashton Smith. It appears in a number of Lovecraft's stories, such as "The Haunter Of The Dark" (Liber Ivonis), "Dreams in the Witch-House" (Book of Eibon) and "The Shadow Out of Time" (Book of Eibon).

The book was passed down by secret cults to the present day. Never printed until the 20th century, there are many editions which vary widely, from tablets to scrolls. Editions include:  the Kishite Version; The Punic (1600 B.C.); The Greek Edition; The Latin Liber Ivonis (10th-11th century); Livre d'Ivon (13th century); and the only printed version, the Adkins and Jones edition of the Latin text (A.D.1937). A key text in the Tsathogguan Cycle.