She was the most famous spokesperson for civil rights, at a time when the idea of equal rights for people of color was very politically incorrect. "We can't afford to have two kinds of citizens," she insisted. "We must have equal citizenship for anybody in our country." And though she was a well-known talker, she also walked the walk. In 1958, at age 74, she made plans to go down to Tennessee to speak at a civil-rights workshop at the Highlander Folk School. The Ku Klux Klan learned about her plans. The day before her trip, the elderly, gray-haired...