Cthulhu by Gaslight takes the Call of Cthulhu roleplaying game to the fog-shrouded streets of Great Britain and beyond. This book is designed for Keepers—those who will be running the game. 

Inside, you'll find: 

Advice for bringing the setting to life.
Information on villainous organizations and occult societies like the Secrets of the Hermetic Order of the Golden Dawn.
Two introductory scenarios designed for players new to the setting.
Scenario seeds to help you pen Cthulhu by Gaslight stories of your own design.
Monsters and Mythos elements unique to Gaslight-era Britain.
Gazetteer of Fear—100+ locations in Britain and beyond.
New occult-based skills, spells, tomes, and rules for astral combat.