We've all had to learn how to be better negotiators - in our relationships, buying products (such as cars or apartment leases), and careers.
Well, there's a whole subset of science devoted to this topic. From general principles to a very specific list of 20 things salespeople will pull on you (and how to respond), these negotiation books have helped out many a previously clueless person.
Get that upper hand! Or at least feel as though you made an informed decision.