Thomas Sowell is one of America's leading voices on matters of race and ethnicity. In his most recent book, "Inside American Education," he surveyed the ills of American education from the primary grades to graduate school with "an impressive range of knowledge and acuity of observation, " according to the "Wall Street Journal." Now in his newest book "Race and Culture," he asks the question: "What is it that allows certain groups to get ahead?" and the answer will undoubtedly create debates for years to come. The thesis of "Race and Culture" is that productive skills are the key to understanding the economic advancement of particular racial or ethnic groups, as well as countries and civilizations -- and that the spread of those skills, whether through migration or conquest, explains much of the advancement of the human race. Whether this body of skills, aptitudes and disciplines is called "culture" or "human capital, " it explains far more than politics, prejudice or genetics. Rather than draw on the experience of one country or one era of history, "Race and Culture" encompasses dozens of racial and ethnic groups, living in scores of countries around the world, over a period of centuries. Due to its breadth and scope, this study is able to test alternative theories empirically on a vast canvas in space and time. Its conclusions refute much, if not most, of what is currently believed about race and about cultures.