Byron M. Roth argues that the current debate over immigration policy is unlikely to produce a satisfying outcome since it takes place uninformed by the science of evolutionary psychology. He thoroughly reviews theory and research indicating that the success of any policy of mass immigration will be profoundly constrained by fundamental features of human nature. Prominent among those features is a natural bias toward one s own kind and a certain wariness of others, making harmony in multi-ethnic societies problematic at best. The problems for such societies are compounded when groups differ in ability and temperament in non-trivial ways. The author explores the history of immigration to the United States prior to World War II and contrasts it with post-war immigration in the West. The evidence marshaled makes clear that the earlier immigration experience of the United States is so different from current patterns that it cannot provide a useful template for understanding and assessing those patterns. In addition, Roth addresses the disturbingly undemocratic nature of the regime of mass immigration imposed by authorities on the citizens of all western nations in defiance of their clearly expressed wishes. He shows that the chasm between elite views and public opinion is so deep that current policies can only be maintained by an increasingly totalitarian suppression of dissent that undermines the very foundations of western democracy.