THE #1 WORLDWIDE BESTSELLER FROM THE ICONIC AUTHOR OF THE DA VINCI CODE AND THE NEW ROBERT LANGDON THRILLER, THE SECRET OF SECRETS. Famed Harvard symbologist Robert Langdon answers an unexpected summons to deliver a lecture at the U.S. Capitol Building. His plans are interrupted when a disturbing object—artfully encoded with five symbols—is discovered in the building. Langdon recognizes in the find an ancient invitation into a lost world of esoteric, potentially dangerous wisdom. When his mentor, Peter Solomon—a long-standing Mason and beloved philanthropist—is kidnapped, Langdon realizes that the only way to save Solomon is to accept the mystical invitation and plunge headlong into a clandestine world of Masonic secrets, hidden history, and one inconceivable truth... all under the watchful eye of a terrifying enemy.