Welcome to "Stirb aufrecht, Kultist!" ("Die upright, Cultist!")
The purpose of this sourcebook is to allow a game of Call of Cthulhu in the Wild West. It's up to the keeper to use the Western background just for one-time experience as a classic Western, or go down all the way to Spaghetti Westerns in the style of the "dollar" movies. But still, it is designed primarily to compete in the Wild West against cthuloid powers.