In 1913, Carl Jung was 38 years old, the most prominent disciple of Sigmund Freud, and on the verge of a psychological crisis that would come closer to destroying him than anything he had previously encountered. Over the preceding months he had severed his professional relationship with Freud, abandoned the theoretical framework that had organized his intellectual life for years, and begun experiencing a series of visions and premonitory dreams of catastrophic destruction, floods of blood covering Europe, civilizations collapsing, the dead walking. When the First World War began in August 1914 and the landscape he had seen in his...