”The Treader of the Dust” / A Cthulhu Mythos Story by Clark Ashton Smith

"The Treader in the Dust" is a short story by American author Clark Ashton Smith. The story introduces Quachil Uttaus and the Testament of Carnamagos to the Cthulhu Mythos, in relation to the tale of an unnamed character who obtains the forbidden tome from a sinister book-seller.