In this book, James Filler traces the history of Being, understood as substance, from Parmenides through the Scholastics and ending with Descartes, in whom this understanding reaches a crisis. He further shows how this understanding inherently leads to serious ontological problems which are unresolvable within a substance ontological approach. It is this substance understanding which has dominated, but this view--with its emphasis on distinctness, independence, and separateness--will create insurmountable problems which ultimately lead to a crisis of thought after Descartes. The book examines this substance understanding, how it has historically shaped the understanding of Being, and how this understanding ultimately becomes ontologically and epistemologically destructive.