His pet screenplay set aside, Khoury worked on his screenplays for several years, building a successful career for himself in London and in Hollywood, before a new agent at the William Morris Agency, who he had joined at that point, read his screenplay of "The Last Templar" and encouraged him to adapt it into a novel. Finally, in September 2002, Khoury began researching and writing the novelized version of his screenplay, which took three years to write. The novel sold quickly, and was first released in the U.K. in 2005. It soon became a "New York Times" bestseller, spending 11 weeks on the hardcover fiction list, and a Number 1 bestseller overseas. It has been translated into 38 languages and published in over 40 countries. Although the book shares some general thematic concepts with those of "Da Vinci Code" author Dan Brown, Khoury devised his plot before Brown's novels were released.