Angels & Demons is a 2000 bestselling mystery-thriller novel written by American author Dan Brown and published by Pocket Books. It revolves around the quest of fictional Harvard University symbologist Robert Langdon to uncover the mysteries of a secret society called the Illuminati and to unravel a plot to annihilate Vatican City using destructive antimatter. The book uses the idea of a historical conflict between science and religion, particularly that between the Illuminati and the Roman Catholic Church. The novel introduces the character Robert Langdon, who is also the protagonist of Brown's subsequent 2003 novel, The Da Vinci Code. It also shares many stylistic elements with its sequel, such as conspiracies of secret societies, a single-day time frame, and the Catholic Church. Ancient history, architecture, and symbolism are also heavily referenced throughout the book. A film adaptation was released on May 15, 2009, though it was set after the events of The Da Vinci Code film, which had been released in 2006.