The psychological testing work of the German-American anthropologist Franz Boas and his school are fundamentally examined for the first time in this book. Alexa Geisthövel portrays the Boazian research strategies and contrasts them to the those of U.S. psychologists in the 1920s who aimed to objectively prove racial differences in intelligence. In addition, she gets to the bottom of relationships between the Jewish anti-racists led by Boas and the German intelligence psychologists and racial researchers in order to make visible the different styles of scientific racism in the U.S. and Germany as well as links between racism and anti-racism in the period between the world wars.