Dan Brown's new book

"The Lost Symbol," will hit shelves Sept. 15, it was announced Monday by his publisher, Doubleday. Brown is the man behind the runaway bestsellers "The Da Vinci Code" and "Angels & Demons." With 81 million copies in print, "The Da Vinci Code" is the bestselling hardcover adult novel of all time.

"The Lost Symbol" will again feature protagonist Robert Langdon and will continue Brown's historical-religious- conspiracy-thriller tradition. In a new twist, Brown has amped up the action -- the entire novel takes place in 12 hours.

"This novel has been a strange and wonderful journey," Brown said in a statement. "Weaving five years of research into the story's 12-hour time frame was an exhilarating challenge. Robert Langdon's life clearly moves a lot faster than mine."

The news of "The Lost Symbol" is particularly exciting for booksellers, who've been looking forward to Brown's follow-up to "The Da Vinci Code" since its publication in 2003.