H. P. Lovecraft
Volumes from The Cthulhu Mythos.
4 volumes
A Hyperborean grimoire that has come down, Smith says, through a series of manifold translations from a prehistoric original written in a lost language — the Necronomicon's older cousin, from the other end of the correspondence.
A Latin grimoire written in prison by a Flemish sorcerer who claimed to have survived the Ninth Crusade, and printed in Cologne the year after they burned him.
The most famous book that does not exist. A grimoire of pre-human history and summoning rites, surviving in a handful of guarded copies, quoted just often enough to convince generations of readers it was real.
Lovecraft's first invented book, older than the species that later tries to read it — fragments from a library-city that was not built by men.