The Secret War for the Union: The Untold Story of Military Intelligence in the Civil War

It's rare for a modern writer to make a genuinely new discovery about the Civil War, but former intelligence officer Edwin C. Fishel pulls it off in The Secret War for the Union. Having stumbled upon a large collection of previously unknown documents at the National Archives, he describes in this book the undercover operations of the Army of the Potomac. Federal intelligence, by Fishel's account, was crucially important to winning the war, and was of much higher quality than previously assumed. Among other accomplishments, it appears to have played a vital role in the Union victory at Gettysburg. This surprise--and a few others--await serious readers.