Though people have been waging war and spying on each other since ancient times (ask Julius Caesar), changes in technology have altered our methods. This entry in the Code Breakers and Spies series (7 titles) explores a particularly pivotal time in human development: WWI, when technological advancements made war, espionage, and code breaking even more complicated than they had previously been. This text-heavy volume delves into the electronic communications of WWI, American reluctance to get involved and the resulting delay in the development of U.S. intelligence, various types of ciphers that were used and broken throughout the war, and widespread postwar paranoia. Occasional sidebars on different methods and individuals, such as Mata Hari, break up the text, but ultimately this is a well-presented discussion of a high-interest topic that will draw older researchers.