"Leave now, or die " Those words-or ones just as ominous-have echoed through the past hundred years of American history, heralding a very unnatural disaster-a wave of racial cleansing that wiped out or drove away black populations from counties across the nation. While we have long known about horrific episodes of lynching in the South, this story of racial cleansing has remained almost entirely unknown. These expulsions, always swift and often violent, were extraordinarily widespread in the period between Reconstruction and the Depression era. In the heart of the Midwest and the Deep...