Five Best Books on Military Intelligence in the Civil War

1. In 1959 Edwin Fishel discovered, in the National Archives, the intelligence files of the Army of the Potomac still wrapped in the red ribbons they had been bound with at the end of the Civil War. A National Security Agency analyst, Fishel realized that all the histories of the Civil War had been written with little or no understanding of the role of intelligence. A key figure turned out to be Col. George H. Sharpe, who, by 1863, had created a fully functioning and potent intelligence operation—the Bureau of Military Information. Prior to the Battle of Chancellorsville in 1863, the bureau’s analysis had provided the Union’s Maj. Gen. Joseph Hooker with an accurate estimate of Gen. Robert E. Lee ’s strength, the location of every brigade-size unit, and a complete picture of the region’s roads and the enemy’s main supply-route railroad. Hooker’s battle plan (which failed for other reasons) was built around this information. Two months after the battle, the bureau’s efforts would prove critical to the Union victory at Gettysburg. There, Sharpe’s men transmitted one of the most important intelligence reports in the history of the U.S. Army—the information that told Maj. Gen. George Meade how thin Lee’s reserves were. Even by today’s high-tech standards, the operations of Sharpe’s agency stand as nothing less than brilliant.