With the American Civil War, the nation saw many firsts—the loss of 600,000 lives, the destruction of $5 billion worth of property, and lasting wounds that endure to this day. Military warfare advanced to amazing new levels of expertise with aircraft balloons, submarines, iron-clad warships, Gatling guns, trenches, a military draft, and organized espionage. The Civil War probably involved more spying, including more people, than any other conflict in our history.

During the Civil War, everybody was spying on everybody else, and little was done on either side to stop the enemy's espionage. The Pennsylvania farmer differed little from the South Carolina plantation owner. Everyone looked the same; regional accents were easy to imitate; and adept agents had little trouble crossing lines posing as civilians or military officials. Shoe clerks, lawyers, grande dames, actresses, even housewives—all joined in the espionage game, and many survived to tell about it. This generation that revered the romantic novelists and poets made up the rules as they went along and adhered to a "gentleman's code" of conduct.

Initially, neither the Union nor the Confederacy had a security organization, no secret service. The capitals of the North and South, Washington and Richmond, lay only 100 miles apart and were obvious targets for spies. Union agents effortlessly maneuvered in and out of Richmond while Confederate spies easily set up headquarters in Washington. However as both sides suffered embarrassing defeats from careless security, organized intelligence programs gradually emerged. The North established its first secret service bureau. Similarly, the South created the Signal Bureau; men using blue and red flags carried on an unending correspondence in cipher signaling to men with spyglasses. An invaluable tool in the game of espionage, the spyglass was frequently used by both sides to observe enemy camps, troop movements, and battle positions.

Civil War spies improvised, experimented using trial and error, and remained determined. The whole story of the triumph and tragedy of civilian and military spy networks will never be known. Countless agents did die; many classified facts were never recorded; and with the fall of the Confederacy, the South's secret service papers were burned. Nevertheless, the intricate systems of today's modern espionage, the Secret Service and the CIA, reflect these first approaches to covert operations.

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