Lovecraft: A Look Behind the "Cthulhu Mythos" is a 1972 non-fiction book written by Lin Carter. It was originally published by Ballantine Books in 1972. The introduction notes that the book is not intended to be a biographical work on H.P. Lovecraft himself but more a social history of the growth of those using his Mythos in their own works.
Lin Carter attempted in this work to define what was and was not "part of" the Mythos. His criteria for inclusion were such that The Colour Out of Space was NOT considered by him to be part of the Mythos. Lin Carter defined his approach thus:
"[T]he mere mention of a Mythos name in an otherwise self-contained story cannot be taken as proof that the story belongs to the Mythos,"
He excludes stories that do not "borrow from or build upon the system of the Mythos" as well as stories that do not "contribute a new portion of background lore to future stories in the Mythos."
Using his own system, he arrives at the following list as being his 'canon' Mythos works:
- "The Nameless City"
- "The Hound"
- "The Festival"
- "The Call of Cthulhu"
- "The Dunwich Horror"
- "The Whisperer in Darkness"
- "The Dreams in the Witch House"
- "At the Mountains of Madness"
- "The Shadow Over Innsmouth"
- "The Shadow out of Time"
- "The Haunter of the Dark"
- "The Thing on the Doorstep"
- "History of the Necronomicon" (short essay)
- Fungi from Yuggoth (poem)
Although his conclusions are wildly at odds with accepted wisdom today, his basic principles in attempting to pin down and create a formula for the Mythos is not especially different from later attempts, most notably in recent decades Chaosium's Call of Cthulhu roleplaying game.