Julius Ludwig August Koch was born 1841 in the small town of Laichingen (Württemberg) in the Southwest of Germany. After working as a chemist for about seven years, he studied medicine in Tübingen from 1863 to 1867. First he worked as a physican and later in a private mental hospital in Göppingen. From 1874 to 1898, he was director of a state mental hospital in Zwiefalten (Württemberg). Koch died in 1908 after a long period of suffering in Zwiefalten. Being deeply routed in a Christian faith and having much interest in moral and ethical issues, Koch published some philosophical works 'Epistomological investigations' (Erkenntnistheoretische Untersuchungen, 1882), 'Outline of philosophy' (Grundriss der Philosophie, 1885) and 'Reality and its knowledge' (Die Wirklichkeit und ihre Erkenntnis, 1886). In this papers he tried to bring together critical Kantian philosophy and Christian conviction. In 1888 he published a 'Short Textbook of Psychiatry' (Kurzgefasster Leitfaden der Psychiatrie), where he mentioned the term "psychopathic inferiority" for the first time (Psychopathische Minderwertigkeiten). The following work, focussing on this issue with the title 'Psychopathic Inferiority' (Die psychopathischen Minderwertigkeiten, 1891-1893), became one of the fundamental texts concerning the concept of disorders of personality, which are in use today. In this book, published in three parts, he tried to describe the hole field between psychic normality and psychoses. Only the first and biggest part deals with psychopathological symptoms which we now think to be essential for personality disorders. Koch differentiates between "disposition" (Disposition), "burden" (Belastung) and "degeneration" (Degeneration), assuming a graduation. "Disposition" should be the mildest disorder, turning into normality, whereas "degeneration" turns to psychosis. Koch believed, that on the basis of all degrees of "psychpathic inferiority" there was a congenital defect of the constitution of the brain. To be consistent, he demanded that the individuals in question should not be punished as hard as people without this disorder by the courts, and proposed to open up special institutions beside the usual prisons. Beside this, Koch describes in the other parts of his book vividly for example acute and chronical organic psychoses and obsessions. Although psychiatric disorders are classified different today, Kochs work keeps its great importance for the concept of personality disorders, further more one can find very exact and detailed descriptions of a multitude of psychpathological symptoms, which are worth reading them today.