Sure most people know that Stalker and Metro games are based on books. And after finishing the game fans usually search for books to stay in that world some more time.
But that was a very big surprise for me to find out that Assassin's Creed and The Witcher are books adaptations too! I always thought they are separated products with original plot and characters.
Anyway, are there some games based on books or even movies you know? C'mon, surprise me even more!