Rich in world history and political power, veiled in secrecy, and rife with rituals and arcane symbols -- from art and architecture to the images that adorn our currency -- the Freemasons arose from ambiguous origins centuries ago to play a major role in drafting the initial documents of the United States, and even in constructing the intricate landscape of Washington, D.C., itself a virtual mystery by design. These puzzles lay the foundation for Dan Brown's serpentine thriller, The Lost Symbol, and also raise provocative questions. Why do some Masonic symbols remain obscured, while others are hidden in plain sight? Which presidents were the embodiments of Masonic ideals? What is the significance of the construction of the Library of Congress, Washington National Cathedral, the Washington Monument, the Capitol, and the physical layout of Washington, D.C.'s roadways and cul-de-sacs? And to what secretive end do they all lead?