Aspects of fiction or fictionality have long intrigued and puzzled philosophers across a surprisingly wide range of the subject, including metaphysics, epistemology, logic, philosophy of language, and aesthetics. What is fiction exactly, and how is it distinguished from nonfiction? One prominent set of problems relates to fictional names (such as “Sherlock Holmes,” “the Time Machine,” “Casterbridge”), concerning how they might fit into a general semantics for natural languages. Should they be eliminated by paraphrase or should they be acknowledged as proper names, albeit referring to nonreal items? Related problems arise for ontology. Should we admit fictional entities into our ontology, affording them some kind of being (as abstract entities, perhaps, or as possible objects)? Or again, should we find ways to eliminate them? Another difficulty stems from the fact that well-developed fictional characters in realist novels can often seem more real than actual people. Not only are they spoken and thought about but they can also occupy a significant role in ordinary people’s lives, including their emotional lives. How can this be explained? How can people respond with such powerful feelings to beings they know are merely made up? Also, how is it that readers sometimes have difficulty imagining the content of stories? Philosophers writing in aesthetics about literature as an art form have explored the modes of representing fictional characters, the values storytelling might have, and the potential for works of literary fiction to convey truths about the real world. Finally, appeals to fiction are sometimes made to explain whole areas of discourse, such as mathematics or morals, where there is a reluctance to admit familiar kinds of propositions as literal truths because of their ontological commitments. Thus, “fictionalism” has been promoted: the idea that strictly speaking it is better to view the discourse as a species of fiction, even while acting as if the discourse contained straightforward truths.