The fair treatment encountered by black ballplayers when they traveled to other nations lasted only as long as the baseball season there. If they wanted to return to the land of their birth, as 99 percent did, the players would once more live in a system that placed obstacles in their paths and constantly reminded them that, because of their skin color, they occupied an inferior position. Segregation smacked the black player twice—it forced him to compete in a separate league, and it subjected him to further abuse while playing within that league. On and off the field, athletes faced the sting of bigotry.

Jim Crow

The roots of unfair treatment stretched back into the depths of slavery and the resulting hatred that accompanied the freeing of the slaves following the U.S. Civil War of 1861-1865. In 1828 a...