John Green (born August 24, 1977) is an American author, YouTuber, podcaster, and philanthropist. His books have more than 50 million copies in print worldwide, including The Fault in Our Stars (2012), which is one of the best-selling books of all time. Green's rapid rise to fame and idiosyncratic voice are credited with creating a major shift in the young adult fiction market. Green is also well known for his work in online video, most notably his YouTube ventures with his brother Hank Green.