The world's most celebrated thriller writer returns with his most stunning novel yet--a propulsive, twisty, thought-provoking masterpiece that will entertain readers as only Dan Brown can do. Robert Langdon, esteemed professor of symbology, travels to Prague to attend a groundbreaking lecture by Katherine Solomon--a prominent noetic scientist with whom he has recently begun a relationship. Katherine is on the verge of publishing an explosive book that contains startling discoveries about the nature of human consciousness and threatens to disrupt centuries of established belief. But a brutal murder catapults the trip into chaos, and Katherine suddenly disappears along with her manuscript. Langdon finds himself targeted by a powerful organization and hunted by a chilling assailant sprung from Prague's most ancient mythology. As the plot expands into London and New York, Langdon desperately searches for Katherine . . . and for answers. In a thrilling race through the dual worlds of futuristic science and mystical lore, he uncovers a shocking truth about a secret project that will forever change the way we think about the human mind.