The Unbreakable Code

John, a young Diné (Navajo), is frightened to leave his lifelong home on the reservation and move to Minnesota with his mother and new stepfather. The boy's grandfather assures him he'll be all right since he has an "unbreakable code," the Diné language. The man goes on to tell the story of how he and other Dinés were recruited by the Marines and developed a message code based on their native language that helped the U.S. in the Pacific during World War II. — School Library Journal