Text in German. The annotated text-critical edition of this seminal work by Alfred Adler presents the original version from 1912. This makes the state of Adler's theory accessible after his separation from Freud, as he had developed it within the circle around Freud and at the same time against Freud. The variant apparatus documents all changes in the new editions of 1919, 1922 and 1928. This edition can be read like a workshop report from Adler's work on his theory development. The philosophical, psychological and medical-historical interdependencies become clear in the commentary section through the biographical and factual explanations of numerous authors and technical terms named or quoted by Adler. As a result, this edition can serve as a tool for exploring a branch that forms the origin of numerous psychotherapy concepts, with psychosomatic, psychoanalytic or socio-pedagogical ramifications that are still effective today.