After an elderly man jumped from New York's Pulitzer Building in 1911, his death made the front page of the New York Times: "World Dome Suicide a Famous War Spy." By then Pryce Lewis had slipped entirely offstage; but, as Gavin Mortimer reveals, the headline did him justice, speaking to the dramatic, vitally important, and until now untold role he had played in the Civil War. Emigrating to the United States in 1856, Lewis was soon...