This fascinating study in the sociology of knowledge documents the refutation of scientific foundations for racism in Britain and the United States between the two world wars, when the definition of race as a biological concept was replaced by a cultural notion of race. Discussing the work of the leading biologists and anthropologists who wrote about race between the wars, Dr. Barkan argues that the impetus for the shift in ideologies of race came from the inclusion of outsiders--women, Jews, and leftists--into the mainstream of scientific discourse.