The Heart of a Ninja series by Chris Warnky offers an insider’s look into the world of ninja training, drawing from his own experiences as a ninja warrior. The series begins with The Heart of a Ninja: Stretch Your Boundaries, chronicling Chris' three-year training journey. For younger readers, The Heart of a Ninja For Kids: It’s PLAY TIME teaches how to play and become a ninja. In What Just Happened? The Line, Chris describes the anticipation of being in the American Ninja Warrior Walk-On-Line, while What Just Happened? The Run shares powerful lessons from his runs. Four Traits of a Ninja explores key ninja characteristics, and Twelve Traits of a Ninja delves deeper into the ninja path, showing how these traits can enrich anyone’s life.