Secret War for the Union: The Untold Story of Military Intelligence in the Civil War by Edwin C. Fishel. Houghton Mifflin Company, New York. 1996, 734 pages.

It was the neglected records of the Union Army’s Bureau of Military Information and it would take nearly 40 years of study, before this book was published.

There is so much written about the American Civil War, down to not only battles but individual engagements that it is rare to find a book that offers a new perspective on this conflict. These records show how the Confederate and Union armies gathered and used intelligence to plan some of the most infamous Civil War battles, such as Antietam and Gettysburg. This volume will re-shape the way you will come to know the Civil War.

The book opens with the 1861 Battle of First Bull Run and the utter failure of intelligence by the Union, leading President Abraham Lincoln to concentrate more resources on the gathering of intelligence. This focus included a discretionary fund to pay spies that would report to him alone. Lincoln would discover that the acquisition of intelligence was less of a challenge than keeping it safe from leaks. At Bull Run, Confederates were given the Union’sl plans to advance on Manassas.

The early seeds of American counter-intelligence were born in the American Civil War. You will read the responsibilities of the Pinkerton detectives was far more than just protecting the President, but included a counter-intelligence arm and information gathering operation.

Union Gen. George McClellan’s reluctance to engage the Confederates was due in part to Pinkerton providing exaggerated numbers and refusing to amend them when a clearer picture emerged about Confederate troop numbers.

It was a complex issue of reluctance to adjust based on a mindset Pinkerton established with the first assessment of southern troop strength. Even a hasty retreat by Confederate Gen. Joseph Johnston at the Virginia Peninsula should have indicated that the numbers were not large in that area of operation.

Interesting aspects covered in the book include Confederate President Jefferson Davis’ few house servants and his driver being spies. One house slave was actually a free woman of high intellect who played the role of servant well.

One African American woman in Fredericksburg communicated threatening activity to Union handlers using her clothesline code. Balloons were also attempted by the Union to collect information. Union Gen. Joseph Hooker created all-source intelligence, taking independent fragments to corroborate information.

Women spies were used by both sides, and the book includes a story of sisters engaged to several Union officers in a ruse to gather intelligence. During the Battle of Antietam in 1862, a preacher mingled with Confederate units to collect information for the Union. In June 1863, of the 14 Confederates units arrayed in Gettysburg, the Union knew where ten were.

Editor’s Note: Cmdr. Aboul-Enein acquired his interest in the American Civil War as an undergraduate student at the University of Mississippi. He wishes to thank Greg Elder for providing this book and an excellent education in the grounds of the Gettysburg battlefield. PS1 (AW⁄SW) David Tranberg, USN provided valuable edits to this column while on deployment to Afghanistan.