The Big Book of Madness is a co-operative deck-building game in which the players are magic students who must act as a team to turn all the pages of the book, then shut it by defeating the terrible monsters they've just freed.
Each player has their own element deck that they build during the game and use for several purposes, such as learning or casting a spell, adding a new element to their deck, destroy or healing a curse. Spells allow you to support your playmates, improve your deck, draw cards, etc. — but the monsters from the book fight back. Each comes with terrible curses that are triggered every turn unless you dispel them in time. They will make you discard elements, add madness cards to your deck, or lose spells...
If you manage to turn six pages and defeat all of the monsters, you win the game!