A book by Friedrich von Junzt which translates to 'Nameless Cults.' This was a contribution to the Mythos by Robert E. Howard. Lin Carter in 'Lovecraft: A Look Behind the Mythos' says: The earliest of his [Howard's tales] that was deliberately written as a contribution to the Mythos was a short story called "The Children of the Night" (Weird Tales, April-May, 1931). In that story he mentioned the Necronomicon, Cthulhu, Yog-Sothoth, and Tsathoggua, and invented a minor godling called Gol-goroth and another of those ancient books of eldritch lore, the Unasussprechlichen Kulten, by a German scholar named Von Junzt. In writing these Lovecraftian tales, Howard and his colleagues generally followed Lovecraft's example. A case in point is this tome by Von Junzt. In another Cthulhuoid story, "The Black Stone" (Weird Tales, November, 1931), Howard picked up and elaborated on the data presented in the earlier story: the Unaussprechlichen Kulten (he tells us) was published in Dusseldorf in 1839; the title translates as Nameless Cults; the tome is sometimes known as "the Black Book"; a cheap and faulty English translation was pirated in London by Bridewall in 1845; a carefully expugated edition appeared from the Golden Goblin Press of New York in 1909. All of this specific data-places, dates, names of translators. bibliographical data on editions-tends to half-convince the reader that the book in question is real. In fact, unless you happen to be a bibliographical expert, you are hard put to say with any certitude whether this or that book mentioned in a Mythos story is real or was invented by the author of the story! Another story, "The Thing on the Roof," picks up and elaborates on both Justin Geoffrey and Von Junzt, and introduces Xuthltan, who plays a major part in yet another tale, "The Fire of Asshurbanipal," not to be published for some years.
See also: Friedrich von Junzt