Top Secret Files : The Civil War, Spies, Secret Missions, and Hidden Facts From the Civil War by Stephanie Bearce

The pigpen cipher, the Devil's Coffee Mill, and germ warfare were all a part of the Civil War, but you won't learn that in your history books! Discover the truth about Widow Greenhow's spy ring, how soldiers stole a locomotive, and the identity of the mysterious "Gray Ghost." Then learn how to make a cipher wheel and send secret light signals to your friends. It's all part of the true stories from the Top Secret Files: The Civil War. Take a look if you dare, but be careful! Some secrets are meant to stay hidden . . . Ages 9-12
Binding: Paperback / softback