
Several chapters also delve into Mal'akh's history with Peter Solomon: many years earlier, Peter bequeathed a large sum of inheritance money to his rebellious son, Zachary, who then fled the Solomon household and led a reckless life in Europe until he was arrested and imprisoned in Turkey for smuggling drugs. He infiltrated the organization in order to obtain an ancient source of power, which he believes Langdon can unlock for him in return for Peter Solomon's life. Mal'akh is revealed to be a Freemason with tattoos covering almost his entire body. He later explains to Langdon that he too has been in contact with Mal'akh and wants Langdon's assistance in rescuing Peter. Before she can arrest him, however, she and Capitol Police Chief Trent Anderson are assaulted by Warren Bellamy, the Architect of the Capitol and a Freemason, who then flees with Langdon in the confusion. Langdon explains that he was unaware of its contents, but Sato, refusing to believe it, attempts to take Langdon into custody. Sato then confronts Langdon with the security x-ray taken of his bag when he entered the Capitol which reveals a smaller pyramid in the package Langdon brought in response to the request by the kidnapper posing as Solomon's assistant. Examining Solomon's hand, they discover a clue leading them to Solomon's Masonic altar in a room in the Capitol's sub- basement, where they find a small pyramid lacking a capstone, with an inscription carved into it. and that his capture is more important than Peter's rescue, although she refuses to elaborate. Sato claims that Mal'akh poses a threat to the national security of the U.S. Langdon meets Inoue Sato, the head of the CIA's Office of Security. Mal'akh then contacts Langdon, charging him with finding both the Mason's Pyramid, which Masons believe is hidden somewhere in Washington, D.C., and the Lost Word, lest Solomon be murdered.

When Langdon arrives at the Capitol, however, he learns that the invitation he received was not from Solomon, but from Solomon's kidnapper, Mal'akh posing as Solomon's assistant, who has left Solomon's severed right hand in the middle of the Capitol Rotunda in a recreation of the Hand of Mysteries. Solomon has also asked him to bring a small, sealed package which he had entrusted to Langdon years earlier.

Renowned Harvard symbologist Robert Langdon is invited to give a lecture at the United States Capitol, at the invitation apparently from his mentor, a 33rd degree Mason named Peter Solomon, who is the head of the Smithsonian Institution. As of January 2013, there were 30 million copies in print worldwide. It was number one on the New York Times Best Seller list for hardcover fiction for the first six weeks of its release, and remained on the list for 29 weeks. On its first day the book sold one million in hardcover and e-book versions in the U.S., the UK and Canada, making it the fastest selling adult novel in history.

It had a first printing of 6.5 million (5 million in North America, 1.5 million in the UK), the largest in Doubleday history. Released on September 15, 2009, it is the third Brown novel to involve the character of Harvard University symbologist Robert Langdon, following 2000's Angels & Demons and 2003's The Da Vinci Code. 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 Lost Symbol is a 2009 novel written by American writer Dan Brown.
