In undertaking to produce a theoretical and historical critique of test diagnostics, I began by looking at the history of psychological tests and the reasons for their development and practical use. In the course of the work it became clear that the Nazi period was the least well researched, but at the same time the one that posed the most questions: What did psychologists do in the Third Reich? How was the field of psychology able to develop? How was it obstructed or encouraged, supported or abandoned? These questions led me into uncharted areas on which few reports existed and about which the German postwar generation knew little, except through hearsay.

A first look at the material, especially scientific publications from the Nazi period, confronted me with a multitude of facts that defied organization. There had been racist typology, but it did not seem possible to understand the history of German psychology in this period solely in terms of ideological Nazification. There had been practical, diagnostic psychology, particularly in the armed forces; there had been professional psychologists; and - in the middle of the war - examination regulations had been introduced for a certificate recognized by the state. But the history of German psychology could also not be described simply as an instrumentalization for the goals of expansion and oppression. There had been dismissals, and some scientists had been persecuted; but the common opinion that psychology had been politically subjugated did not seem to explain all the facts.