Matthew Evans offers a new interpretation of the ancient Greek philosopher Parmenides of Elea, challenging the standard view that he simply denied the possibility of change. Instead, it shows that Parmenides was deeply invested in the enterprise of the empirical sciences, and that in his view the proper development of this enterprise depends on distinguishing sharply between the things we encounter in the world around us and the underlying nature or reality of these things. Blending clear explanations with close readings, the book reveals how Parmenides's ideas have shaped philosophy and science from the beginning.