Few authors have achieved such great commercial success as Dan Brown, whose next novel — “The Lost Symbol” — is scheduled to be published this fall, more than six years after “The Da Vinci Code” lifted Brown from obscurity.

That earlier book has sold more than 80 million copies worldwide, was adapted into a movie and made hits out of Brown’s previous novels, including “Angels & Demons,” whose film version is now in theaters.

Brown calls his new novel a “strange and wonderful journey,” and adds that the life of his protagonist Robert Langdon “clearly moves a lot faster than mine.”

Publisher Knopf Doubleday has announced a 5 million first printing of the new book.

“Lost Symbol” took far longer to complete than his previous projects. In his increasingly rare public statements, Brown has lamented that he can no longer fly on commercial planes, because of autograph seekers, and expressed shock at the vehemence of the questions he faced while promoting “The Da Vinci Code.”

“As soon as ‘The Da Vinci Code’ was published and had become a runaway success, I found myself in a firestorm of controversy,” Brown wrote in a court statement for a copyright infringement suit filed against him (and eventually rejected) in London.

“I had never experienced this kind of media attention, and it was very difficult at times (especially the criticism from Christians). Often at my book signings, I found myself interrogated publicly by an angry Christian scholar who quizzed me on details of Bible history from the novel.”