This book describes Descartes's The Passions of the Soul as a foundational work of the Enlightenment, a precursor of later notions of the historicity of the human, and the first psychology of modern type: to understand and heal ourselves, we look not outward at the world in immediate relation to it, but inward, at the self, its brain, and its past history. Special attention is given to Descartes’s account of imagination and its problematic impact on passion and volition.