"1939 - 1945" . . "Indians of North America Fiction." . . "The unbreakable code"@en . "The unbreakable code" . . . . . . . "The Unbreakable Code"@en . . . . . . . . "Because John is afraid to leave the Navajo Reservation, his grandfather explains to him how the Navajo language, faith, and ingenuity helped win World War II."@en . "Because John is afraid to leave the Navajo Reservation, his grandfather explains to him how the Navajo language, faith, and ingenuity helped win World War II." . . "Juvenile works"@en . "Juvenile works" . . . . . . . . . . . . . . . . . . . "Fiction" . "Fiction"@en . . .