Scientific racism claims that biological inheritance determines the character and behavior of social groups we identify as races. Despite its history of oppression and genocide, the scientific defense of racial inequality demonstrates a disturbing persistence. Murphy Ballen’s study of scientific racism in Great Britain and the United States in the 1920s and 1930s appropriately deals not with its demise but with its retreat. Making extensive use of private correspondence, Ballen relates leading scientists' published research to their person ....