 Less well-known, at least among the world of English-speaking psychiatry, is Jaspers’s lasting contribution to the field of psychiatry that preceded his philosophical work, and in retrospect transpires as not wholly unrelated it, at least in its common guiding spirit. During his distinguished career as a psychiatrist, Jaspers achieved an outstanding contribution to psychiatric thinking, later called ‘The Heidelberg School’ and led by Kurt Schneider. As a young man, he authored a number of scientific articles on homesickness and crime, on intelligence tests, on hallucinations – all illustrated with detailed case histories. Also, Jaspers published reports of the mental pathology of Van Gogh and Stirnberg. Among these, of special importance are his outstanding article from 1910, in which he introduced his method and fundamental principles regarding ‘mental processes’ and ‘personality development’, and an article on the phenomenological method in psychiatry from 1912, which established his pioneer status as a first commentator on the phenomenological study of subjective experiences at the conscious level. At the age of barely thirty, in 1913, while he was working as a physician in the psychiatric hospital at Heidelberg, Jaspers published his Allgemeine Psychopathologie: Ein Leitfaden für Studierenden, Ärzte und Psychologen (General Psychopathology: A Guide for Students, Physicians and Psychologists). The aims of this book were to provide the framework of the scientific field of psychopathology and its related facts and approaches, not only for practitioners in this filed but also for interested intellectuals. This framework covers the problems and methods that capture the body of knowledge of the field rather than empirical evidence or a system based on a theory. Instead of deciding between the different existing approaches of his time, he stressed their peculiarity that entails the inherent justifications and the way they might complement each other and together portray the many sides of the psychopathological science. The hint of the spirit of his existential philosophy, yet to become expressed, is apparent in his declaration in the preface of the book, according to which “in psychopathology it is dangerous merely to learn the matter, our task is not to ‘learn psychopathology’ but to learn to observe, ask questions, analyze, and think in psychopathological terms”. However, despite the very impressive of the achievement of the mentioned book, which within the German speaking world was recognized by leading psychiatrists as a monumental achievement in the field, it marked the culmination of Jaspers’s psychiatric productivity. Just two years later, Jaspers moved away forever from psychiatric practice and medicine in general, first towards psychology and then philosophy. Interestingly, though, Jaspers saw fit to revise and expand the text in a few of its several editions. The first edition is the shortest. In the second and third editions, there were minor changes. The most considerably revised and expanded edition is the fourth, which appeared in 1942. To a large extent, the integration of many ideas from his then already mature existential philosophy from the thirties onwards, which more than doubled the scope of the text, in fact amount to a new version of the book. Now, the subtitle that appeared in the earlier versions was removed and in the preface Jaspers indicates its high aim of satisfying the demand for knowledge, not only for physicians but for all who make mankind their theme. In this enlarged version of the book, the imprint of Husserl’s descriptive psychology is apparent in the attempt to address the inner mental experiences of mentally ill people (mainly schizophrenic patients) and regard them as indicative of the general phenomena of human consciousness, i.e.: delusions, modes of ego-consciousness, and modes of emotions. At the same time, the imprint of Wilhelm Dilthey (1833–1911) was perceptible in the centrality given to the distinction between ‘understanding psychology’ (Verstehende Psychologie), which relates to meaningful and comprehensible connections that are inherent in one’s personality and biography, and ‘explaining psychology’ (Erklärende Psychologie), which focuses on causal connections that are mainly rooted in  biology.1]