Nazi propaganda defamed Albert Einstein as a racial and political enemy of the national community [Volksgemeinschaft] and scorned his work as the quintessence of "Jewish-corrupted" natural science. Representatives of so-called German or Aryan physics, such as Philipp Lennart, for example, declared that theoretical physics, and especially Einstein's theory of relativity, was invalid and maintained that true knowledge of nature could only be acquired through experimental research by "Nordic" scientists. The caricature mocks Einstein's political and scientific activity: "Authorial fame seems to be ‘relative.’ The brown book that Einstein had published, and that agitates against Germany, turns out to be an advertisement for the Communist International. Einstein recoils from the book." The "brown book" in question was a collection of materials published by Communist writers and journalists to document National Socialist crimes and perpetrators.
