John Green is a best-selling author, and YouTube celebrity — not to mention a philanthropist, educator and sponsor of a professional British football team.

The author of  “The Fault in our Stars” and “Paper Towns,” Green stirs up a frenzy among young adults with each new story. His new book, “Turtles All the Way Down” follows Aza, a young girl trying to live an average teenage existence while reining in her self-destructive thoughts.

Green talks about his own mental health, creating a YouTube empire with his brother Hank, and some of the things he loves the most — be warned, there are Mountain Goats involved.