Oswald Bumke is a central figure in twentieth-century German psychiatry, having had a considerable influence on its development as one of its best-known representatives. His time in Leipzig from 1921 to 1924 and subsequently in Munich up to the mid-1930s saw the second major phase in his scientific work, during which he laid the basis for the renown he still enjoys as a result of his specialist encyclopaedic textbooks and manuals summarising the current knowledge of his time. At the beginning of the 1920s he made his stand on the burning issues of the day and thus influenced the conceptional history of the subject. For instance, he proposed his own philosophical psychology, rejecting the experimental psychological approach of Emil Kraepelin. By challenging the libido theory and the dynamic unconscious he weakened the impact of Sigmund Freud and psychoanalysis on German scientific psychiatry. Moreover, Bumke strongly opposed the prevailing concept of degeneration and its main protagonist Ernst Rüdin. Owing to the political and social developments at the time, however, he was not able to raise much support among his colleagues.