Feature Guest- John Green

John Green is a best-selling author of young adult novels. His latest book 'The Fault in our Stars', about a teenage couple who meet at a cancer support group has sold more than 270,000 copies and is being made into a movie. He and his brother Hank have had 200 million YouTube views of their Vlogbrothers channel weekly video exchanges to each other. The Green brothers have also launched 'CrashCourse'- an educational YouTube channel featuring teaching videos they've made on the sciences and humanities.