The view that propositional knowledge is knowledge of facts (rather than propositions) is prima facie rather appealing, especially for realistically minded philosophers, but it is difficult to square with the referential opacity of knowledge attributions of the form ‘S knows that p’. For how could Lois Lane know that Superman can fly and ignore that Clark Kent can fly if knowledge is a two-place relation between an agent and a fact and the fact that Superman can fly just is the fact that Clark Kent can fly? The chapter critically reviews some attempts to tackle the problem and then proposes a new solution which exploits the contrastivist claim that knowledge is a three-place relation between an agent, a fact and a contrast