 Theories employing possible worlds terminology have been found to be very useful in philosophy, e.g. when engaging in thought experiments; distinguishing various claims in metaphysics, or in the philosophy of language, mind, knowledge or ethics; and in areas other than philosophy, like linguistics, modal logic, and probability theory. Many have found the status of these worlds and their contents to be puzzling, to say the least. What are they? Where, if anywhere, are they supposed to be? How are we supposed to discover facts about them? Isn’t it extravagant to believe that just because a situation is possible, it must in some sense exist? Modal fictionalists take theories committed to the existence of possible worlds, merely hypothetical situations, non-actual but possible objects etc. to be strictly and literally false, and so they avoid the problems of believing in possible worlds. Nevertheless, they claim, they can enjoy the benefits of using these seemingly problematic theories.