Rene Descartes, one of the fathers of modern philosophy, is often portrayed as a strict rationalist whose works theorized a radical, unresolvable split between mind and body. It is widely believed that he rejected imagination, a hybrid psychological power somewhere between mind and body, as inessential to cognition. In Descartes's Imagination, the first book in more than fifty years to examine the role of imagination in Descartes's philosophy, Dennis L. Sepper argues that such interpretations are exaggerated, if not simply wrong. Sepper's study is based on a thorough analysis of all Descartes's writings, especially the less-known early works, and his new perspective shatters the strictly dualistic view of the philosopher's thought. Sepper shows how Descartes began his investigations of human knowing with an inquiry into the power of imagination, which premodern philosophy assigned a determinate role in the thought process. Descartes Imagination offers a critical reconception of Descartes. It shows him to be less a rationalist than an investigator of the shifting planes of consciousness; less a proponent of pure intellectual inquiry than a philosopher of active, physically engaged intelligence. Descartes was not a dualist so much as one who recognized that, since matter and mind could never explain each other, humans would have to learn to live well as both.