The Lost Symbol is a 2009 novel written by American writer Dan Brown. It is a thriller set in Washington, D.C., after the events of The Da Vinci Code, and relies on Freemasonry for both its recurring theme and its major characters.
Hardcover edition
Robert Langdon is a fictional character created by author Dan Brown for his Robert Langdon book series: Angels & Demons (2000), The Da Vinci Code (2003), The Lost Symbol (2009), Inferno (2013) and Origin (2017). He is a Harvard University professor of Religious Iconology and "symbology".
Prof. Robert Langdon portrayed by Tom Hanks in Angels & Demons