Navajo Codebreakers

I was amazed at the story of the Navajo code breakers of WWII.  I had never heard anything about their story, which I found a little strange.  Their skills and ability to communicate using an unbreakable code were extremely important during the war.  What I found really interesting was that the code was never broken.  It was such a brilliant idea to use the Navajo language.  None of the enemies had any understanding of Navajo words so the code was unbreakable.  This is an amazing piece of history that I wish I knew more about.