The Thirteenth Throne
Compendium of All Observed Rituals
Thicker than the Enkhiridion but probably less trustworthy.
When casting Rituals, your rituals take much longer (2d4 hours or longer, and there’s no way to speed it up!) but you can use it to improve the efficicency of the ritual. Roll a d6 whenever you use a ritual; on a 6 the spell used to fuel it isn’t expended. Describe how the book helped.
This book purports to contain all known rituals barring the diabolical ones banned by the Church of Morrow. It’s exhaustingly pedantic.
QUIRK: You become obsessed with pointless ceremony and ritual.