The main thing Joann Van Buren says she remembers about Timothy McVeigh is the $50 bill he wanted her to break. That, and the two men who accompanied him. One day before he tore a hole in the nation's psyche with the bomb that destroyed Oklahoma City's Murrah Federal Building, McVeigh, Van Buren says, pulled up to the little Subway sandwich shop where she worked in Junction City, Kansas, driving the yellow Ryder truck that would contain the bomb. Van Buren didn't pay any particular attention to them at first. Another clerk waited on the men, but when they tried...