"More than 30 people tell personal stories about the nonviolent struggle for civil rights, then and now, not only the leaders but also ordinary citizens who bear witness to "transforming moments" when they suddenly found the courage to try to change things. David Dinkins, New York City's first black mayor, served with the U.S. Marines in World War II; at home, he had to use the back of the bus. A white woman remembers herself as a child after the...