[Radek]

Everything essential has already been said. My opinions:
1. The Book of Misfortune. It's either an intend (it's a misfortune!) or a spell planned in the early stages of the game development but not implemented later. At any rate, the book can only be sold.
2. The Living Stone. I consider it a poetic hyperbole to a Lava Hound.
3. Raskallion and Brinbath. Perhaps, another relict from early stages of the game development. Later on, another questgiver took care about Raskalion.
4. The key and the hammer. I got both by killing the king. I simply went and killed him in his throne room. Well, the hammer is rather useless and the treasure does not contain anything super special. Therefore, I reloaded my game.