Ren#65533; Descartes is commonly portrayed as a strict rationalist, a philosopher who theorized a radical, unresolvable split between mind and body. In this long-overdue examination of the role of imagination in Descartes's thought, Dennis Sepper reveals a Descartes quite different from the usual dualistic portrayals and offers a critical reconception of the genesis and nature of the philosopher's thought. In a vigorous analysis of the less-known early works, Sepper finds that initially Descartes assigned the imagination a central role in the mind's activity. Although Descartes eventually lost confidence in the philosophy of imagination, an early understanding of its central role in cognition came to shape the most fundamental notions of his mature philosophy. Sepper's radical reassessment of Descartes ultimately raises new questions about the development of modern philosophy.