This book proposes a different perspective on actual queries within the field of ontology. Focusing on non-standard objects, it offers original answers to classic problems in metaphysics, such as individuation, reference, existence and non-existence. The chosen ontological fields are, for this purpose, ontologies that essentially involve human social practices such as intentional objects, fictions, mental illnesses or social entities. Even though the papers can be read independently, readers will discover a number of original intersections that provide fresh points of entry to contemporary metaphysical issues. By dealing with entities that are not so frequently addressed in related works, the book also contributes to broaden their perspective on ontology. Both scholars and students will find it particularly useful to have a survey about non-standard abstract entities that can provide new topics for their research.