During the next session, my players will get their hands on a book of prophecy from a temple in the chaos wastes. The book is supposed to be a cryptic tome that the players can use to get guidence and hint about what to do. However, it's not as easy as just opening the book and reading it. The true mening of the prophecy is hidden within the text and is not without its risks to unravel.
So the general idea I have is that they will carry this tome with them and try to consult it for guidance when unsure about where to go or what to do in a general sense. But each attempt to read the book brings with it chances of mental damage.
Has anyone else used forbidden tomes in their games where players could learn usefull stuff from them, but with a high risk? I am thinking of doing something like a Education(Willpower) check where failures lead to stress and Chaos Stars give temporary insanities?