To start GMing* Call of Cthulhu 7th edition, would I need both the Keeper Rulebook and the Investigator Handbook, or just the previous?

(I did google and check out some reviews online, but they failed to make this entirely clear – or I failed to understand it. That's also possible. Maybe I picked the wrong reviews.)

*or is it "keepering"? :)


Experienced Keepers

The rules for play and for character creation are present in the Keeper's Guide, and it appears to be meant to be a stand-alone book for a Keeper who is already familiar with the game, and its common setting of the 1920s. If a Keeper were shifting to this edition from an earlier one, the Keeper's Guide would be sufficient.

New Keepers

Those new Keepers without a grounding in the game, its inspirational material, its setting and conceits, and/or who wish to be in tune with the advice given to new players and with the point of view fostered for play will need to consider getting, or having access to, both.


Likewise, players will find all the information they need to create and ground characters in the 1920s setting if they obtain the Investigator's Handbook and will require nothing from the Keeper's Guide. If they later intend to run the game as well as play it, however, they will need both.


It should be noted that the system rules are available in a PDF Quickstart format from the usual sources as well as Chaosium, so they can be investigated prior to making a purchase.

The Table of Contents for the Keeper's Guide

  1. Introduction

  2. HP Lovecraft and the Cthulhu Mythos

  3. Creating Investigators
  4. Skills
  5. Game System
  6. Combat
  7. Chases
  8. Sanity
  9. Magic
  10. Playing the Game
  11. Tomes of Eldritch Lore
  12. Grimoire
  13. Artifacts and Alien Devices
  14. Monsters, Beasts, and Alien Gods
  15. Scenarios (2)
  16. Appendices

421 pages of content

The Table of Contents for the Investigator's Handbook

  1. Introduction
  2. The Dunwich Horror
  3. Creating Investigators
  4. Occupations
  5. Skills
  6. Investigator Organizations
  7. Life as an Investigator
  8. The Roaring Twenties
  9. Advice for Players 10 Reference
  10. Character Sheets

268 pages of content

  • \$\begingroup\$ Thanks, that was quite thorough. Good to know I won't have to buy both books right away, when it comes to 7th ed. :) \$\endgroup\$ – OpaCitiZen Aug 28 '16 at 10:48
  • \$\begingroup\$ You are most welcome, it was my pleasure~ \$\endgroup\$ – Runeslinger Aug 28 '16 at 10:51

All you need to play the game is in the Keeper's Guide. I've managed to run a successful campaign using just that. We started with one of the two very good premade adventures found inside and then went into homebrew.

The Investigator's Handbook gives more options for the players and provides setting material for the 1920's setting to help inspire both GMs and players during campaign and character creation. There's more occupations, as well as more information about each one, and a few optional skills for them. Aside from that you don't need the Investigator's book at all to play the game. You can play just fine using just the keeper book and screen, which with how complicated some of the rules are (particuarly combat) I strongly recommend.

  • \$\begingroup\$ Hi blackskullthunder, and welcome to the site! Check out our tour to see how we work here, and when you reach 20 rep, you'll be able to join us in Role-playing Games Chat. \$\endgroup\$ – doppelgreener Jun 25 '17 at 11:44

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