De Vermis Mysteriis
This forbidden book De Vermis Mysteriis, or The Mysteries of the Worm by Ludwig Prinn is the invention of young Robert Bloch. His mentor Lovecraft gave him the Latinized version in a letter dated January 25, 1935: "If Prinn's immortal work is in Latin, you ought to give the title in that language-hence my change in two places (in yr ms.) to DE VERMIS MYSTERIIS (Concerning / of the worm / the mysteries). Also, since knowledge of elementary Latin is so universal, I've modified the statement concerning your limitations in that tongue. Still more, I've supplied just a tantalizing fragment of that hellish invocation: (tibi, Magnum Innominandum, signa stellarum nigrarum et bufoniformis Sadoquae sigillum ..." (To thee / great Not-to-be-Named / the signs / of the stars / black / and / of the toad-shaped / Tsathoggua / the seal ...)."
("The Haunter of the Dark," "The Shadow Out of Time")
See also: Ludwig Prinn and Robert Bloch