CHAPTER 5: SANITY AND INSANITY
Sanity is one of the most important concepts in Call of Cthulhu, as characters are just as likely to go insane from seeing unspeakable horrors as they are to actually be killed by them. Each character has a set number of starting Sanity points, and when faced with a terrifying or grotesque encounter the character has to roll a d100 lower than their current Sanity points. Failure (and sometimes even success!) means the character loses a certain number of Sanity points. If the character loses 5 or more from a single encounter, he has to roll against an Idea (Intelligence x 5) check--in this case, failure on the roll is a good thing, as it represents the fact that the character was able to rationalize away what he saw without grappling with its full horror; whereas, success is bad because it means the character understands the true depth of what he's seen and thus will be driven temporarily insane. [I actually forgot this last part during my one-shot--mea culpa!] The other way to go temporarily insane is to lose 20% of current Sanity points in one game hour.
The game provides a small random table to roll on for the particular type of insanity the character suffers, but the book strongly suggests (and I agree) that it's better for the Keeper to choose a form of insanity that fits the character and the circumstances he or she is encountering. If a character is driven temporarily insane by encountering a gigantic winged apparition, it makes more sense to give him or her a phobia of birds than to give him compulsive hand washing.
The chapter has quite a thorough discussion of various mental health disorders and their treatments, nicely divided between "classic era" (1920s and 1930s) and modern-day.
As a character's Sanity points dwindle, he or she becomes more and more unreliable in the field and should eventually be retired in favor of another investigator. There are a few ways to increase Sanity points: small awards by the Keeper after the end of a successful adventure; psychotherapy (very slow, taking months of game time); and by increasing a skill to 90% or above (not sure the rationale for this one--why is the "discipline and self-esteem" gained by becoming a really good Fast Talker going to increase my Sanity?).
CHAPTER 6: MAGIC
Access to magic is very much handled by Keeper discretion. No characters start out with spells or with the right to learn spells through experience, and it's quite possible the Keeper may decide not to make magic available to PCs at all. But if the Keeper does, magic has to be learned through reading Mythos Tomes--books that contain vital secrets of the universe but that are also likely to drive men mad (and increase the Cthulhu Mythos Skill). There's some really nice description of various books to make these more than D&D-style "Spell Scrolls." The one odd thing I found is that the books, as listed, take several weeks or even a year of steady reading in order to gain the knowledge contained within them--this simply doesn't fit many gaming styles, where characters are moving at a relatively quick pace in order to deal with urgent matters.
Spellcasting itself is almost guaranteed to drain Sanity points, and success usually depends on the number of Magic Points (equal to POW) that a character has. Here again, there's a nice degree of description and ritual involved, so that casting a spell is an involved, important thing that fits within the atmosphere of the game--no energy blasts at the drop of a dime.
CHAPTER 7: THE CTHULHU MYTHOS
This short chapter provides an overview and timeline to the various deities and beings talked about in Lovecraft's work. I found it hard to make much sense of, but Keepers who have delved deeply into the Mythos may find it a helpful summary. Although I like that this single book has everything needed to play the game, information of this sort would be better if only the Keeper had access to it.
CHAPTER 8: THE NECRONOMICON
The Necronomicon is H.P. Lovecraft's most famous invention, next to Cthulhu itself. The legendary tome is the most potent source of information about the Mythos, but also the most likely to drive its readers stark raving mad. I like that the text gives descriptions of a few different versions of the book, again helping enrich the game's atmosphere.
CHAPTER 9: HOWARD PHILLIPS LOVECRAFT
A short bio of Lovecraft; none of this is necessary to play the game, but it's a respectful way to acknowledge the author of the game's source material.
CHAPTER 10: DE RERUM SUPERNATURA ("THE NATURE OF THINGS SUPERNATURAL")
An odd chapter, which is basically a summary of how various Mythos-related beings and tomes are translated in other languages: Arabic, Greek, Hebrew, and more. This one's only going to be appreciated by Keepers really into authentic treatment of linguistic history.
CHAPTER 11: MENTAL DISORDERS
This is a non-mechanics oriented discussion of a variety of mental disorders. Some of this repeats information found in the chapter on Sanity & Insanity, and I have no idea why the two chapters weren't combined.
Next Time: Monsters, Gods, and Spells!