“The rules are that each writer should invent a demon-god or two, and a crumbling tome of blasphemous eldritch lore, and, as often as not, a milieu - generally a decaying backwater of old towns slouching into desuetude, with an omnipresent aura of ancient witchcraft and obscure cults in their past… and generally their present, too.” Lin Carter on creating the Cthulhu mythos.