In this book, Vasilis Politis argues that Plato's Forms are essences, not merely things that have an essence. Politis shows that understanding Plato's theory of Forms as a theory of essence presents a serious challenge to contemporary philosophers who regard essentialism as little more than an optional item on the philosophical menu. This approach, he suggests, also constitutes a sharp critique of those who view Aristotelian essentialism as the only sensible position: Plato's essentialism, Politis demonstrates, is a well-argued, rigorous, and coherent theory, and a viable competitor to that of Aristotle. This book will appeal to students and scholars with an interest in the intersection between philosophy and the history of philosophy.