My longtime friend and colleague Dr. Thomas Sowell has just published a revised and enlarged edition of “Discrimination and Disparities.” It lays waste to myth after myth about the causes of human differences not only in the United States but around the globe. Throughout the book, Sowell shows that socioeconomic outcomes differ vastly among individuals, groups and nations in ways that cannot be easily explained by any one factor, whether it’s genetics, sex or race discrimination or a history of gross mistreatment that includes expulsion and genocide.