Military intelligence for both North and South during the Civil War was collected from search towers, balloons, horseback couriers and cameras. It was transmitted by signal flags, flashes, telegraphy and sensitive plates. Both armies concentrated on snarling, foiling and shooting out installations. By emphasizing these early steps in signals and communications, as well as including the better-known ladies and gentlemen who penetrated the enemy lines to spy, the author has produced a fascinating record that is both war history and technological history. Facts and anecdotes gathered from the widely scattered sources and personal stories of the period are well organized into the kind of book which proves again that truth is stranger than fiction.