Robert Langdon is the protagonist of the novel. Langdon appears in five novels written by Dan Brown. Langdon is a Harvard professor of art history and the fictional field of symbology. In Brown’s first two novels, Langdon found himself wrapped up in two very controversial and religious mysteries. The first centered around the appointment of a new Pope and the second focused on the revelation that the Holy Grail is actually a bloodline, not a physical cup. These mysteries have created some celebrity for Langdon prior to the opening of The Lost Symbol; by this point in Brown’s loosely connected series, Langdon is weary of people approaching him with apparent knowledge of his new reputation.

Langdon is a highly intelligent man who relies on his wits rather than his brawn. In fact, Langdon harbors a terrible fear of heights and confined spaces due to a childhood accident in which he fell down a well. In this novel, Langdon’s involvement in the mystery is more about circumstance than anything else. Langdon is drawn into the situation because he happens to be the person Peter Solomon trusted to safeguard a sealed package that his family had been protecting for generations.