Stuart A. Kallen has written more than 350 nonfiction books for children and young adults. His books have covered a wide arc of human history, culture, and science. Kallen is also an accomplished singer-songwriter and guitarist in San Diego, California.

In 1944 and 1945, battles between the United States and Japan raged in the South Pacific. In the midst of exploding bombs and rattling bullets, a special group of Marines helped US forces send secret messages back and forth. They spoke in a code they'd created based on the Navajo language, a code the enemy was never able to crack. Learn about the heroic Navajo code talkers, who used their unbreakable code to help the United States beat Japan in World War II.