The Robert Langdon series is a set of thriller novels by American author Dan Brown featuring the titular character, Robert Langdon, a Harvard professor of symbology. The series consists of five novels, each of which follows Langdon as he unravels complex mysteries and uncovers hidden truths using his knowledge of symbols and religious history. The novels are known for their fast-paced action, intricate puzzles, and attention to detail, drawing on real-world historical events and art. The series has been widely popular, with each novel becoming a bestseller and two being adapted into successful films starring Tom Hanks as Langdon.