Aimed at the younger generation of the members of the Japanese Society of Psychiatry and Neurology, this journal is going to launch a series of reviews entitled "`Basic Problems in Psychiatry' in the 21st Century: Classics of Psychiatry Series", which introduces major figures and their research in the development of modern psychiatry. This paper is an introduction to the series that summarizes the historical position of each of the figures. Since the dawn of modern psychiatry, there have been two genealogies of psychiatry: one focusing on psychosis and the other on neurosis. The former, called descriptive psychiatry, focuses on the observation and description of symptoms and behaviors of psychotic patients. At the turn of the 19th century into the 20th century, Kraepelin proposed the classification of mental disorders by the disease entity concept, as represented by the two major psychoses, "dementia praecox (schizophrenia)" and manic-depressive illness. This proposal started a major trend in clinical and biological psychiatry. Descriptive psychiatry took the dualistic approach of psychological understanding as well as the search for a somatic basis in the diagnosis of mental disorders. On the other hand, the genealogy of psychodynamic psychiatry developed to explore the intrapsychic world of patients with neurosis, such as hysteria patients. Clinicians and investigators belonging to this genealogy tried to understand the mental disorders, including psychosis, in a monistic manner, assuming the existence of the Freud's unconscious. They contributed to the development of the theories and techniques of psychotherapy. The mainstream of psychiatry in Japan had been under the influence of German psychiatry since Shuzo Kure introduced it at the beginning of the 20th century. Even after the WWII, this trend remained, due to the contributions by Yushi Uchimura who popularized the Heidelberg School of psychopathology established by Jaspers and developed by Schneider. In his later years (1972), Uchimura published a monograph entitled "Basic Problems in Psychiatry", which was an excellent review focusing on historical thoughts and theories on the structure of mental disorders. We decided to title our serialized articles "`Basic Problems in Psychiatry' in the 21st Century," after the title of Uchimura's book.
 Authors' abstract