Kate Shoup 
Life As a Navajo Code Talker in World War II [PDF ebook] 

One of the most influential struggles of World War II was fought behind the scenes, the battle for intelligence. Enormous resources were devoted to breaking the enemy’s code, a feat that could decide the outcome of a battle. Among the reasons for the allied triumph is the creation of a code based on the Navajo language, a code that was never broken. This is the story of how these code talkers lived, worked, and ultimately influenced World War II.