Emil Kraepelin (1856-1926) whose hundred and fiftieth birth anniversary we are celebrating this year, is one of the most renowned figures of psychiatry. His Memoirs published in 1983 provide insight on the individual. In his early career he lived in Würzburg, Munich, Leipzig, Leubus, Dresden, and then in Dorpat in 1886 (as visiting professor) where he stayed for five years, in Heidelberg (as regular professor) from 1891 to 1904, and lastly in Munich. Kraepelin ranks among the great clinical medicine forerunners who followed in Kahlbaum's footsteps. For him, the foremost task of scientific psychiatry was to circumscribe pathological entities. At the foundation of Kraepelin-inspired scientific psychiatry lies the notion of the <<clinical study>> of disease, as opposed to the <<symptomatic>> approach (5th edition of the Treatise), whereby it is no longer concerned with the study of mental disorder in terms of symptoms but rather in terms of conditions of occurrence, evolution and outcome thereof. This method produced two well-known results: the unification and recognition of <<manic-depressive insanity>>, and the definition of <<early-onset dementia>> (dementia praecox). These results are described in the Treatise of Psychiatry which has had eight editions during the author's lifetime (from 1883 to 1915), and which presents Kraepelin's systematic nosography covering the entire field of mental illness. Such an innovative method required special tools capable of exploring not only the symptoms, as had been done previously, but the pathological process per se: therefore, Kreapelin created a systematic method to conduct psychiatric research and founded a Research Establishment divided into different sections (histopathology, topographic histology, serology, genealogy). Alois Alzheimer and Franz Nissl, among others, were closely associated with his work. Kreapelin's thought was not set, however, and by the end of his career it took a turn toward a more comprehensive type of psychiatry (1920) taking into account the social aspects (<<social psychiatry>>). From the therapeutic and institutional viewpoints, Kraepelin remained faithful throughout his life to the no-restraint practice by abolishing any restraint methods wherever he worked; by establishing a trust-based relationship with the patients; by allowing the patients to correspond and by opening the institution to visitors. Additionally, he participated actively in the struggle against alcoholism and syphilis. He is also one of the initiators of cross-cultural psychiatry (<<comparative psychiatry>>). Although he lead a medical career, Kraepelin was also interested in experimental psychology, and he thought of his works in that area as more important than his clinical achievements. He was closely connected with Wilhelm Wundt with whom he worked (at the Institute of Psychology of Leipzig where Kraepelin was one of the first medical doctors to collaborate with Wundt) and then exchanged letters. Some of his experimental works, including the elaboration of series of tests aimed at studying the psychic effects of certain substances, herald the advent of psychopharmacology. Lastly, his Memoirs and Poems give insight on the intimate person of Kraepelin, as well as putting his affective life in perspective.