Inferno is a 2013 mystery thriller novel by renowned American author Dan Brown and the fourth book in his Robert Langdon series, following Angels & Demons, The Da Vinci Code and The Lost Symbol. The book was released on May 14, 2013 by Doubleday. It was number one on the New York Times Best Seller list for hardcover fiction and Combined Print & E-book fiction for the first eleven weeks of its release, and also remained on the list of E-book fiction for the first seventeen weeks of its release.