A Cthulhu Mythos anthology is a type of short story collection that contains stories written in or related to the Cthulhu Mythos genre of horror fiction launched by H. P. Lovecraft. Such anthologies have helped to define and popularize the genre.
Tales of the Cthulhu Mythos, edited by August Derleth and published by Arkham House in 1969, is considered the first Cthulhu Mythos anthology. It contained two stories by Lovecraft, a number of reprints of pieces written by members of Lovecraft's circle of correspondents, and several new tales written for the collection by a new generation of Cthulhu Mythos writers. It was published in an edition of 4,024 copies.
Derleth prefaced the collection with "The Cthulhu Mythos", an outline of his (sometimes controversial) views on the development and content of the Mythos. In this introduction, Derleth prematurely declared the genre to be dead--"for certainly the Mythos as an inspiration for new fiction is hardly likely to afford readers with enough that is new and sufficiently different in execution to create a continuing and growing demand".
The Cthulhu Mythos is a shared fictional universe, based on the work of American horror writer H. P. Lovecraft.
The term was first coined by August Derleth, a contemporary correspondent of Lovecraft, who used the name of the creature Cthulhu—a central figure in Lovecraft literature and the focus of Lovecraft's short story "The Call of Cthulhu" (first published in pulp magazine Weird Tales in 1928)—to identify the system of lore employed by Lovecraft and his literary successors. The writer Richard L. Tierney later applied the term "Derleth Mythos" to distinguish between Lovecraft's works and Derleth's later stories.
Authors of Lovecraftian horror use elements of the Mythos in an ongoing expansion of the fictional universe.
Robert M. Price described, in his essay "H. P. Lovecraft and the Cthulhu Mythos," two stages in the development of the Cthulhu Mythos. The first stage, termed the "Cthulhu Mythos proper" by Price, was formulated during Lovecraft's lifetime and was subject to his guidance. The second stage was guided by August Derleth who, in addition to publishing Lovecraft's stories after his death, attempted to categorize and expand the Mythos.