For Matt Cavanaugh, nothing worked. He couldn't help the ones he loved the most, his marriage was on the rocks. Inspired by a near-death combat experience, Cavanaugh transformed himself from failure to fit with an act of radical generosity. He donated a kidney to a stranger, an act that also helped save the lives of seven others dying of kidney failure. Then, just months after surgery, Cavanaugh became the only living kidney donor and fastest American ever to run the toughest self-supported ultramarathon series in the world - RacingThePlanet's 4 Deserts Grand Slam - twice counted among the world's greatest endurance races by Time. Best Scar Wins follows Cavanaugh as he uses every lesson and experience, slogan and saying he picked up from his military career to navigate the world's worst deserts across four continents - from scorpions to penguins - on a mission to save lives. The eleven lessons in this astonishing adventure story - including how to expand your endurability - illuminate a path that anyone can follow to become more than they were before. In a call to live generously in support of others, Best Scar Wins shows you how to embrace your scars as triumphs - not as experiences that hold you back but as lessons that empower you to achieve more than you ever thought possible.