Carl Gustav Jung's 1903 essay "On the Manic Mood" (Original German title: Über hysterisches Verlesen) is an incisive exploration of a psychological state at the nexus of emotional exaltation and pathological dysfunction. Written during his early years as a psychiatrist, this work demonstrates Jung's commitment to understanding the psyche beyond the confines of purely medical or neurological interpretations. It illustrates his burgeoning interest in the interplay between emotional states and unconscious processes, and lays the groundwork for the more sophisticated psychological theories he would develop in later years. This updated edition features a modern, accessible translation that makes Carl Jung's early scholarly works-originally written for an academic audience-readable and engaging for contemporary readers. The translation is complemented by an afterword by the translator, which explores the philosophical foundations, historical context, and continuing relevance of Jung's ideas. The afterword not only clarifies this particular work for today's audience, but also situates it within the broader trajectory of Jung's intellectual and clinical development. Supplemented by a detailed timeline of Jung's life and work and other carefully curated supplementary materials, this edition provides rich context by embedding Jung's theories in their personal, cultural, and historical milieu. By removing dense academic references and adopting clear, straightforward language, this translation invites newcomers and seasoned scholars alike to explore the origins of Jungian psychology with fresh insight and accessibility. In this essay Jung examines mania not merely as a pathological anomaly but as a phenomenon with profound psychological significance. He acknowledges the clinical features of manic episodes-exuberance, excessive energy, and an almost boundless sense of possibility-but seeks to understand their roots in the human psyche. Jung's observations reflect a nuanced view of mania, emphasizing its psychological depth and its potential to reveal fundamental truths about the human condition. Here, Jung explores the mood disturbances characteristic of manic states, contributing to the early understanding of bipolar disorder, which was then often referred to as manic depression. He presents a comprehensive study of the clinical manifestation of what the author describes as "manic mood," a condition associated with psychopathic inferiority and characterized by submanic symptoms that often date back to adolescence. The text outlines several case studies, detailing the patients' hereditary factors, early life, and course of illness. Key symptoms identified include emotional instability, flight of ideas, distractibility, excessive busyness, and a cheerful mood, often mixed with other psychopathic traits. We also see his earliest understandings of Will and the heterogeneous nature of consciousness: The role played by intellect is mostly a rather secondary one, in that at best it lends an apparently logically compelling series of concepts to the a priori characterological motive, and at worst (very often the usual case) it constructs intellectual motives only after the fact. In general and absolute terms, Schopenhauer expresses this view as follows: Man always acts only as he wills, and yet he acts necessarily; but this is because he is already what he wills, for from what he is follows necessarily all that he does each time.