Dan Brown’s first new novel since The Da Vinci Code was announced yesterday. Inevitably, it involves a global cult and a race against time to unlock a secret formula.

Details of the plot are likely to remain fiercely guarded until much nearer the publication date of September 15, but intrigue centres on whether Brown’s vast and conspiracy-crazed international fanbase can divine any clues about the novel from its title: The Lost Symbol.

The story, a sequel to The Da Vinci Code, unfolds over 12 hours and again features the Harvard symbologist Robert Langdon. It has taken Brown five years to write but only in the past few days has he settled on a title bland or enigmatic enough to give away none of his new subject matter.

Since The Da Vinci Code was unleashed on a largely unsuspecting world in 2003, Brown’s success has been such that every carefully drip-fed hint of his plans has been cannibalised by fan sites and rival publishers.

When the long-rumoured sequel was provisionally listed for publication in 2006 under the title The Solomon Key, it led to a rash of pre-emptive books about how to unlock the Solomon Key.

The new title was deliberately chosen to be “as opaque as possible”, according to a source close to the project. “Dan Brown is so phenomenally successful that anything he says in relation to his books can spawn a whole publishing industry in itself.” Brown had previously hinted that his next novel would be set in America and concern freemasonry, just as The Da Vinci Code delved into the religious organisation Opus Dei, and its predecessor, Angels & Demons, tackled a secret society called the Illuminati. His books have antagonised Christian groups and upset sensitive lovers of fine English prose but their protests have been drowned out by record-breaking sales.

Brown’s publisher announced The Lost Symbol at the London International Book Fair yesterday. Booksellers immediately predicted that it would be the biggest-selling book of the year, sparking the sort of hysterical expectation last witnessed with the publication of the seventh and final Harry Potter book, Harry Potter and the Deathly Hallows, in 2007.

Brown’s last four novels (the first three of them republished after the phenomenal success of The Da Vinci Code) are now the first, second, third and fourth bestselling adult paperback novels in British history, according to Nielsen Bookscan. Appetites will be whetted further next month with the release of a film version of Angels & Demons. Like The Da Vinci Code adaptation, it is directed by Ron Howard and stars Tom Hanks.

Sonny Mehta, chairman and editor in chief of the Knopf Doubleday Publishing Group, Brown’s US publisher, said: “This is a great day for readers and booksellers. The Lost Symbol is a brilliant and compelling thriller. Dan Brown’s prodigious talent for storytelling, infused with history, codes and intrigue, is on full display in this new book. This is one of the most anticipated publications in recent history, and it was well worth the wait.”

Jason Kaufman, Brown’s US editor, said: “From the first page, Dan’s readers will feel the thrill of discovery as they follow Robert Langdon through a masterful and unexpected new landscape. The Lost Symbol is full of surprises.”

Brown said: “This novel has been a strange and wonderful journey. Weaving five years of research into the story’s 12-hour timeframe was an exhilarating challenge. Robert Langdon’s life clearly moves a lot faster than mine.”

Toby Bourne, Waterstone’s head of fiction, said: “Customers constantly ask our booksellers, ‘When is the new Dan Brown out?’ It’s incredibly exciting that we now have an answer.”

The Da Vinci Code’s British paperback edition (published in March 2004) spent 120 weeks in The Sunday Times’s Top Ten.

Angels, demons and symbols

- Dan Brown was born on June 22, 1964, in Exeter, New Hampshire. Before becoming a novelist, he was a singer-songwriter and pianist, releasing albums, including one entitled Angels & Demons in 1994

- His first book was called 187 Men to Avoid: A Survival Guide for the Romantically Frustrated Woman. One of the types of men it recommended avoiding were those who write self-help books. It was co-written with his wife, Blythe, and published under the pseudonym Danielle Brown in 1995

- In 2004, spurred by the success of The Da Vinci Code, all four of Brown’s novels were in the US bestseller list in the same week

- The Da Vinci Code has sold more than 80 million copies worldwide, making it one of the bestselling books in history

- Brown’s income from The Da Vinci Code has been estimated at about £170 million. It has been translated into more than 50 languages, and the subsequent film adaptation grossed nearly £500 million worldwide. The sequel, Angels and Demons (starring Ewan McGregor) is due for release in Britain on May 15

- Brown has admitted using gravity boots to hang upside down when he has writer’s block, claiming that it gives him a different perspective from which to view his plots

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