Brown, 40, has sold 25 million copies of his fourth novel, making the "Da Vinci Code" one of the fastest selling adult novels ever and bringing Brown an estimated $50 million in the past two years, the New York Times reported.
Brown, besieged by fans and objectors, has stopped giving interviews but did respond to questions by e-mail, the newspaper reported.
"I have no idea how real celebrities handle their fame," Brown wrote. "I'm just a guy who wrote a book, and it still can turn into a circus at times when I go out in public."
Brown wrote his life changed dramatically, such as borrowing his book at the airport when he forgot his picture ID. He said he still rises at 4 a.m., though, to write every day.
Doubleday officials said they expect a manuscript of the sequel in 2006. It will be set in Washington and focus on the secretive world of Freemasons, the newspaper said.