Dan Brown's new novel, "The Lost Symbol," is due out in September

For those who have enjoyed Dan Brown's previous books "Angels & Demons" and "The DaVinci Code," Robert Langdon is back in the long awaited and much anticipated "The Lost Symbol." The U.S. and U.K. release date is set for September 15. The book's plot has been kept a complete secret, so its anybody's guess what its about. Given Brown's own hints, however, it is presumed to deal directly with Freemasonry.