Call of Cthulhu Rpg Keeper Rulebook: Horror Roleplaying in the Worlds of H.p. Lovecraft (Call of Cthulhu Roleplaying) [Hardcover]
Nameless Horrors: Six Dreadful Adventures for Call of Cthulhu (Call of Cthulhu Roleplaying) [Paperback]
S. Petersen's Field Guide to Lovecraftian Horrors: A Field Observer's Handbook of Preternatural Entities and Beings from Beyond the Wall of Sleep (Call of Cthulhu Roleplaying) [Hardcover]