Western philosophical orthodoxy places many aspects of other people’s lives outside the scope of our knowledge. Demonstrating an alternative to this view, however, this book argues that Jean-Paul Sartre’s application of his unique psychoanalytic method to Gustave Flaubert is the culmination of his project to show that it is possible to know everything there is to know about another person. It examines how Sartre aims to revolutionize our way of thinking about others by presenting his existential psychoanalysis as the means to knowledge of both ourselves and others. By so doing, it highlights how his determination to solve the longstanding philosophical conundrum about other minds drives him not only to incorporate insights from Descartes, Hegel, Husserl, Freud, Marx, and Beauvoir into his philosophy, but also to supplement and enhance his philosophy through the development and application of a new form of psychoanalysis. Sartre’s Existential Psychoanalysis integrates, for the first time, Sartre’s psychoanalysis into his overarching philosophical project. By offering a critical interrogation of the role his psychoanalytical studies played in the development of his existentialism, Mary Edwards uncovers the overlooked philosophical significance of his existential psychoanalysis and brings it into a new and productive dialogue with current research in the fields of philosophy, psychology, and psychotherapy.