<p>Our story begins in Greek and Roman antiquity, where the concept of race did not exist, only geography and the opportunity to conquer and enslave others. Not until the eighteenth century did an obsession with whiteness flourish, with the German invention of the notion of Caucasian beauty. This theory made northern Europeans into "Saxons," "Anglo-Saxons," and "Teutons," envisioned as uniquely handsome natural rulers. Here was a worldview congenial to northern Europeans bent on empire. There followed an explosion of theories of race, now focusing on racial temperament as well as skin color. Spread by such intellectuals as Madame de Stael and Thomas Carlyle, white race theory soon reached North America with a vengeance. Its chief spokesman, Ralph Waldo Emerson, did the most to label Anglo-Saxons--icons of beauty and virtue--as the only true Americans. It was an ideal that excluded not only blacks but also all ethnic groups not of Protestant, northern European background. The Irish and Native Americans were out and, later, so were the Chinese, Jews, Italians, Slavs, and Greeks--all deemed racially alien. Did immigrations threaten the very existence of America? Americans were assumed to be white, but who among poor immigrants could become truly American? A tortured and convoluted series of scientific explorations developed--theories intended to keep Anglo-Saxons at the top: the ever-popular measurement of skulls, the powerful eugenics movement, and highly biased intelligence t