In the "Cotton South" before World War II, every task, from plowing to cultivating to harvesting the crop, was done by hand. These labor-intensive practices, coupled with too many farmers -- both tenants and owners -- trying to survive on small, uneconomical farms, kept the region poor, backward, and unmechanized. From 1940 to 1970, however, in the Great Migration, southern blacks and whites thronged to new opportunities in the postwar, industrial North.

In this revisionist study, Donald Holley marshals impressive statistical and narrative evidence to show that mechanization occurred in the...