Eliezer talks a lot about decision theory in his sequences, e.g. the Aumann agreement theorem or the von Neumann-Morgenstern utility theorem. From what I've seen so far, decision theory looks extremely interesting.

Which textbook in decision theory would you recommend to start with? I'd appreciate if the book contained not only theory, but also some exercise/problem section - I have noticed that usually a lecture is not enough to fully grasp a topic. I want a book which will not shy away from mathematical side of the theory.

I have a strong background in mathematics and computer science, but I only know a little about game theory.