The book focuses on a 16-year-old girl named Aza who suffers from OCD. "She feels like she has thoughts that she can't get rid of that kind of feel like they're coming from the outside of her and then she uses compulsive behaviors to try to manage these thoughts that she can't stop having," Green explained.
"I hope people understand, maybe get a glimpse of what it's like to live with this kind of mental illness," he went on. "Writing about the relationship between parents and children in this book was really important to me."
Green has a strong relationship with his fans known as "Nerdfighters" and said his interactions with the online community helped frame the way he approached writing this book.
"The great thing about my job is that I get to hear from teenagers and young people every single day -- but also I was writing for you guys when no one else was reading it, in these like coded blogs that only a few people could read," he said. "That was super helpful to me because I was able to write for a really small audience that was also really generous."
"Turtles All the Way Down" is Green's first novel since his 2012 hit "The Fault in Our Stars."