TIME magazine named him as one of the "Top 100 Most Influential People in the World." Men's Fitness hailed him as the fittest man on the planet. An internationally recognized endurance athlete and bestselling author, Dean Karnazes has pushed his body and mind to inconceivable limits. Among his many accomplishments, he has run 350 continuous miles, foregoing sleep for three nights. He's run across Death Valley in 120 degree temperatures, and he's run a marathon to the South Pole in negative 40 degrees.