Call of Cthulhu The Grand Grimoire of Cthulhu Mythos Magic Hardcover

Master the dangerous and mind-shattering arcana of the Lovecraftian universe with The Grand Grimoire of Cthulhu Mythos Magic from Chaosium Inc.! Written by Mike Mason and Matthew Sanderson, this definitive 224-page full-color hardcover compendium compiles over 550 spells spanning four decades of Call of Cthulhu gaming into one essential Keeper sourcebook.

Fully revised and updated for the 7th Edition rules engine, this master magic tome provides expanded spell casting mechanics, casting costs, alternative spell names, ritual components, and deep guidance on how magic corrupts both minds and reality.

The Ultimate Arcane Reference for Keepers

Magic in Call of Cthulhu is never safe, predictable, or heroic—it is a dangerous distortion of cosmic reality that exacts a heavy toll on the caster's sanity and physical body. The Grand Grimoire of Cthulhu Mythos Magic gathers, revises, and standardizes every spell ever published for the system into a single, beautifully illustrated reference work.

Designed primarily for Keepers running campaigns across any era (Gaslight, 1920s, Modern, or Pulp), this book transforms spellcasting from simple mechanical rolls into atmospheric, narrative-driven events that heighten horror and tension at the table.

Key Features & Arcane Mechanics

• Comprehensive 550+ Spell Catalog: Covers everything from classical summoning rites and warding sigils to reality-bending alien sorcery, complete with standardized 7th Edition stats, casting times, Magic Point costs, and Sanity loss parameters.
• Alternative Names & Historical Variants: Includes historical and regional alias lists for spells, allowing Keepers to present ancient manuscripts containing familiar magic disguised under obscure or forgotten titles.
• Expanded Magic Systems: Features deep-dive rules for casting rituals, magical components, physical gestures, ley lines, folk magic, deep magic, and modifying existing spells on the fly.
• Grimoire Creation & Magical Tomes: Offers guidance on designing unique occult manuscripts, placing magical books as scenario rewards, and managing the slow psychological decay of Investigators who study forbidden arcana.