Tim Ferriss, 39
It’s hard to describe what Tim Ferriss does. Best-selling author? Check. Angel investor? Yup. Chinese kickboxing champion? Yeah, that too. Perhaps the description that best captures Ferriss’ growing influence is one that recently dubbed him the “Oprah of audio.” Not only has his weekly podcast, The Tim Ferriss Show, now reached 80 million downloads, but the self-help guru drives sales of books, teas, sardines, toothpaste and any other product or tool he happens to mention on his uber-popular series. Speaking of Uber, Ferriss was an early investor in the ride-hailing service—and in Facebook, Alibaba, Twitter, Evernote and more—and has been an increasingly sought-after advisor to tech entrepreneurs. His next book, Tools of Titans, comes out in December.