This book presents an historical and conceptual reconstruction of the theories developed by Meinong and a group of philosophers and experimental psychologists in Graz at the turn of the 19th century. Adhering closely to original texts, the contributors explore Meinong”s roots in the school of Brentano, complex theories such as the theory of intentional reference and direct reference, and ways of developing philosophy which are closely bound up with the sciences, particularly psychology. Providing a faithful reconstruction of both Meinong”s contributions to science and the school that arose from his thought, this book shows how the theories of the Graz school raise the possibility of engaging in the scientific metaphysics and ontology that for so long have been considered off limits.