At the Mountains of Madness
Price believes that the basis for Derleth's system is found in Lovecraft: "Was Derleth's use of the rubric 'Elder Gods' so alien to Lovecraft's in "At the Mountains of Madness"? Perhaps not. In fact, this very story, along with some hints from "The Shadow over Innsmouth", provides the key to the origin of the 'Derleth Mythos'. For in "At the Mountains of Madness" is shown the history of a conflict between interstellar races, first among them the Elder Ones and the Cthulhu-spawn.