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.

The House of the Temple is a Masonic temple in Washington, D.C., United States, that serves as the headquarters of the Scottish Rite of Freemasonry, Southern Jurisdiction, U.S.A.