Armies of the late 20th century made liberal use of new technologies, effectively changing the way war has been waged for 100 years. Stealth planes and drones allow armies to spy on and attack their enemies in new ways. GPS technology allows militaries to navigate the world and locate the enemy with more ease. The many battles taking place all over the world at the end of the 20th century culminated in the 21st century's "War on Terror." Readers are...