Keegan brings to life the split-second decisions that went into waging war before the benefit of aerial surveillance and electronic communications. The English admiral Horatio Nelson was hot on the heels of Napoleon's fleet in the Mediterranean and never knew it, while Stonewall Jackson was able to compensate for the Confederacy's disadvantage in firearms and manpower with detailed maps of the Appalachians. In the past century, espionage and decryption have changed the face of battle. Timely information, however, is only the beginning of the surprising and disturbing aspects of decisions that are made in war, where brute force is often more critical.