In ontology, realism and anti-realism may be taken as opposite attitudes towards entities of different kinds, so that one may turn out to be a realist with respect to certain entities, and an anti-realist with respect to others. In this book, the editors focus on this controversy concerning social entities in general and fictional entities in particular, the latter often being considered nowadays as kinds of social entities. More specifically, fictionalists (those who maintain that we only make-believe that there are entities of a certain kind) and creationists (those who believe that entities of a certain kind are the products of human activity) present themselves as the champions of the anti-realist and the realist stance, respectively, regarding the above entities. By evaluating the pros and cons of both these positions, this book intends to focus new light on a longstanding debate.