John Green's new YA novel The Fault in Our Stars vaulted to the top of bestseller lists before it was even released, with sales driven by the proudly dorky fanbase (they call themselves "nerdfighters") that's formed around Green's writing and the YouTubes he makes with his brother, Hank. There's a reason so many adolescents (and, full disclosure, Mercury arts editors) venerate Green's work, both online and off: His books are very, very good.

The Fault in Our Stars is about a girl with cancer who falls in love with a boy with cancer. On paper nothing could be more schmaltzy, but chief among Green's accomplishments here is to remind his readers that sick people are still people—and sick teenagers, moreover, are still sarcastic, existentially tormented, horny, insecure, and all the other things teenagers are capable of being, cancer or no cancer.

Hazel and Augustus meet at a support group, where Augustus confesses that, more than death, he fears oblivion. Hazel—a terminal patient—responds that no one will be remembered forever, and "[if] the inevitability of human oblivion worries you, I encourage you to ignore it. God knows that's what everyone else does." So begins the love story of Hazel and Augustus, star-crossed from day one. It brings them from hospital ICUs to Anne Frank's house in Amsterdam and back again, and it's driven by some pretty weighty questions: Why bother loving someone if you know you're going to die? How are you supposed to lead a meaningful existence when you're so sick you can't even walk up a set of stairs?

Stars is a book about finding and creating meaning, both in stories and in life. "It was important for me personally to think about why we make the choices we do, why we orient ourselves the way that we do, and why we live while we live," Green told me over the phone. "So often the given reason is that we're doing it in order to make a mark or leave a legacy or change the world, and the truth is that if you hold that up to scrutiny, if that's really why you're living, you're living for something that's not only impossible but also sort of destructive... but I do think that it's worth it. I think it's a privilege to be an observer of the universe."

For a complete transcript of our interview with John Green, go here.