This book offers an overview of recent discussions on deflationary approaches to ontology and abstract objects. The essays compiled in this volume constitute previously unpublished, original material aiming at exploring current ideas on deflationary approaches to ontology and their relationship to abstract objects, covering issues ranging from the ontology of mathematics and scientific theories to the semantics of fictional expressions and possible worlds. The complete volume represents a contribution to current debates on the nature and epistemology of abstract entities. Its target audience comprises researchers, professionals, lecturers, and students of philosophy, mainly with interests in metaphysics, ontology and metaontology.