On Thanksgiving night, 1915, a small band of hooded men gathered atop Stone Mountain, an imposing granite butte just outside Atlanta. With a flag fluttering in the wind beside them, a Bible open to the twelfth chapter of Romans, and a flaming cross to light the night sky above, William Joseph Simmons and his disciples proclaimed themselves the new Knights of the Ku Klux Klan, named for the infamous secret order in which many of their fathers had served...