Call Of Cthulhu RPG: Keeper Rulebook

This book, the Keeper Rulebook, contains the core rules, background, guidance, spells, and monsters of the game. It is intended for use by the Keeper of Arcane Lore (the Keeper) - that player who will present the adventure to the other players. You must have at least one copy of this book to play Call of Cthulhu. The other players, the Investigators, should have one or more copies of the Investigator Handbook, containing expanded rules for character creation, skills, occupations, equipment, and more.

448 page hard cover.  7th Edition. Chaosium Inc