This step-by-step, self-contained introduction to the theory of auctions allows students and readers with a calculus background to work through all the basic results in auction theory. Readers will work through the basic independent-private-model, understand the effects of introducing correlation in valuations on equilibrium behaviour and the seller's expected revenue, develop a working knowledge of mechanism design, and be introduced to the theory of multi-object auctions.
This is better than Krishna's book. I think it does the exposition much more smoothly and goes through the probabilistic foundations in such a way as to get the intuitive understanding behind the methods. Of course this is less than 200 pages so it's not very broad in scope. Nevertheless if I ever teach a class in auction theory, this is the book I will be using.