"This well-designed, action-packed entry in the STEM on the Battlefield series provides an overview of how math has been used on the battlefield, both historically and in modern times. Chapters on navigation, cartography, and aeronautics explore how early mathematical principles have led to the technology we have today. But it's the core chapters on cryptography that are likely to be of the highest interest; this introduces simple ciphers, first used in warfare by the ancient Spartans, and other basic codes that were the foundation for the more complicated ones used during both world wars and beyond. Codes have gotten much harder to break, it explains, since the dawn of the computer. Scientific sidebars, wartime photos, and code and cipher charts add information and appeal. Educators beware: classroom notes are about to get a lot more complicated."--Booklist.