"The Negro Motorist Green Book" was an essential tool for the black motorist in the first half of the 20th century. In the American South, the early decades of motoring overlapped with the region's most virulently racist "Jim Crow" era. Black motorists were confronted by challenges largely unknown to white travelers, and a slight misreading of the local racial norms could turn the most commonplace activity into one that brought down on them humiliation, brutality, or death. Many black motorists would not take to the roads without their copy of The Green Book; it was their bible for discovering safe places.