The full title of this book is pretty long: Code Talker: The First and Only Memoir by One of the Original Navajo Code Talkers of World War II. Phew. That's quite a mouthful.
The title tells us a few important things. First of all, it announces the book's theme: it's about the Navajo code talkers of World War II. The title also tells us that this is non-fiction, since the book is referred to as a "memoir." Finally, the title calls attention to what a unique document it is. It's the "first and only" memoir by one of the "original Navajo code talkers."