John Green is an American author of young adult fiction. His books are characterized by their witty, intelligent writing style and thought-provoking themes. Green's novels explore topics such as mental illness, love, and morality. His debut novel, Looking for Alaska, was awarded the 2006 Michael L. Printz Award from the American Library Association. Green's second novel, An Abundance of Katherines, was a finalist for the 2006 Los Angeles Times Book Prize. His third novel, Paper Towns, was published in 2008 and was adapted into a film in 2015. Green's fourth novel, The Fault in Our Stars, was published in 2012 and became a bestseller. The book was adapted into a film in 2014, starring Shailene Woodley and Ansel Elgort. Green has also written several non-fiction books, including Will Grayson, Will Grayson (co-written with David Levithan) and Let It Snow: Three Holiday Romances (co-written with Maureen Johnson and Lauren Myracle). Green's books have been translated into over thirty languages and have sold millions of copies worldwide. He has been praised for his engaging, relatable characters and his ability to tackle difficult topics in a sensitive and thoughtful way.