https://archive.org/details/Understanding_Human_History_Michael_Hart/mode/1up Book arrived used, almost like new a little while ago, it'll still be some time before I'll get around to reading it. Sounds interesting. Excerpt: >As a result, the peoples living in Northern Asia and Europe now have mean IQs of about 100, while the peoples living in sub-Saharan Africa have average IQs of around 70, and those living in a broad intermediate zone (stretching from North Africa across southern Asia and into Indonesia) have average IQs in the 80-90 range. At least four different types of evidence confirm these differences in intelligence: > 1) The results of numerous IQ tests taken over a period of more than 80 years, not just in the United States but in many other countries. > 2) Measurements of the average brain size of the members of various racial groups. > 3) The poor performance (on average) of blacks in Europe and America in economic matters, contributions to mathematics and science, and in games of intellectual skill, such as tournament chess and duplicate bridge. > 4) The extreme backwardness of the countries in the secluded zone of sub-Saharan Africa before they had contact with either Islamic or European civilization.