The essays in this volume, first presented at an international conference held at the University of Urbino, Italy, in 2011, explore the different senses of realism, arguing both for and against its distinctive theses and considering these senses from a historical point of view. The first sense is the metaphysical thesis that whatever exists does so, and has the properties it has, independently of whether it is the object of a person's thought or perception. The second sense of realism is epistemological, wherein realism claims that, in some cases, it is possible to know the world as it exists in and of itself. A third sense, which has become known as ontological realism, states that universals exist as well as individuals. The essays collected here make new contributions to these fundamental philosophical issues, which have largely defined western analytic philosophy, from Plato and Aristotle to the present day.