- Essential manual for running games of Call of Cthulhu, seventh edition - Contains basic rules, background, Keeper advice, spells, and monsters - Exclusive for the player taking on the role of Keeper, responsible for presenting the adventure - Compatible with all previous Chaosium products in the same line - This book is required to play Call of Cthulhu - Investigators can use the Investigator's Guide to expand rules and character options - Recommended for 2 to 6 players, ages 14 and up - Each game lasts approximately 60 minutes - Product in Spanish, ideal for fans of horror and investigation role-playing games