George Washington's name is inseparable from America, and not only from the nation's history. It identifies countless streets, buildings, mountains, bridges, monuments, cities — and people. In a puzzling twist, most of these people are black. The 2000 U.S. Census counted 163,036 people with the surname Washington. Ninety percent of them were African-American, a far higher black percentage than for any other common name. The story of how Washington became the "blackest name" begins with slavery and takes a sharp turn after the Civil War, when all blacks were allowed the dignity of a surname. Even before Emancipation, many enslaved...