Dan Brown likes secrets.

His novels are filled with codes, puzzles and hidden agendas. According to the protagonist of his most successful works, the Harvard professor Robert Langdon, “there are symbols hidden in places you would never imagine”. With the upcoming publication of Brown’s new book, The Lost Symbol, which sets Langdon on the trail of the ultra-secretive Masons, the author’s exploration of these hidden codes is set to continue.

Brown, meanwhile, is something of a mystery himself. Although his breakthrough novel, The Da Vinci Code, has sold more than 80m copies worldwide since its publication in 2003, the reclusive writer has made few public appearances and granted only rare interviews. Which raises the question — what is it he is trying to hide?

He wanted to be a pop star

Although Brown is internationally famous as a novelist, fiction writing was not his first love. After being educated at an exclusive New England prep school, Phillips Exeter, and Amherst College, he travelled west to try his luck as a singer/songwriter in Los Angeles. In 1993, he released his first CD, Dan Brown, which included a song about phone sex called 976-Love. The following year, he released a religiously themed CD, Angels & Demons. It sold less robustly than his novel of the same name published six years later. The real benefit of his trip west, however, was that he met his wife, Blythe Newlon, who was at the time director of artistic development at the National Academy of Songwriters. Brown claims her skills as a researcher and first-look editor have been instrumental in the success of his books.

Indiana Jones he ain’t

In Brown’s work and in rare interviews, he presents an image of teaching as a blood sport. His favourite movie character is the whip-wielding archeology professor Indiana Jones, while his own hero, Prof Langdon, is a ruggedly handsome, globetrotting “symbologist”, who is said to resemble Harrison Ford. The reality of Brown’s own career when he returned to Phillips Exeter as an English teacher is rather different. By all accounts, he was an avuncular, cardigan-wearing classroom presence, more comfortable telling rowdy kids to keep it down at the back of the class than doing battle with albino assassins or Nazis. In this respect, he was following less in the footsteps of Indiana than those of his father, Richard, a famous maths teacher and author of a widely used textbook, Advanced Mathematics: Precalculus with Discrete Mathematics and Data Analysis, which generations of students have no doubt found riddled with as many mysteries as The Da Vinci Code. Even though Brown has given up teaching, the pedagogical urge remains embedded in his work, which often reads more like a history text than pop fiction. “If I’m not learning, I’m usually not engaged,” he once explained. “So I like fiction that teaches.”

His code name is ‘brand now’

Brown is famously obsessed with anagrams, cryptology, riddles and anything else that obscures meaning and teases the brain. He is especially fond of ambigrams, typographical tricks that, for example, allow words or phrases to read the same upside down. His commitment to this particular genre is so deep that he named his leading man after the ambigram artist John Langdon. Such arcane mathematical concepts as Boolean algebra and Fibonacci numbers also figure in Brown’s writing. This playfulness even extends to his book jackets — according to his publisher, clues to the content of The Lost Symbol are embedded in the cover art of The Da Vinci Code, some of which are only legible with the help of a magnifying glass. These include a reference to the sculpture called Kryptos, which is situated in the courtyard of the CIA’s Virginia headquarters. There are also allusions to Freemasonry, Mormonism, and Skull and Bones, an ultra-secret Yale society to which George Bush father and son both belonged.

He may not be the AntiChrist after all

In the run-up to the 2006 release of the film version of The Da Vinci Code, the general public could be forgiven for thinking Satan had chosen this shy Yankee scribbler as his special minion, given the ferocity of attacks on him by the Catholic church and others. In fact, Brown is portrayed by friends, acquaintances and colleagues as a polite, friendly, slightly nerdy man who would not hurt a fly. There is even evidence in his writing and his early musical career that he possesses a strong religious streak. You wouldn’t know this by some of the reactions his work has provoked, however. Soon after the release of The Da Vinci Code, which questions the divinity of Christ, a top Vatican official condemned it as being “stridently anti-Christian… Full of calumnies, offences and ­historical and theological errors regarding Jesus, the gospels and the Church”. Another spokesman urged all good Catholics to boycott the film version, which was also decried by The National Organization for Albinism and Hypopigmentation (Noah), which maintained that the “evil albino” character of Silas could “lead to stereotyping and discrimination against people with albinism”. Despite these protests, and decidedly mixed notices from critics, who seemed more outraged by Tom Hanks’s haircut than any authorial sacrilege, the celluloid Code proved the second-highest grossing film of the year, raking in more than $750m worldwide. This year’s film of Angels & Demons also ran into trouble when the Vatican refused permission for the director, Ron Howard, to film at two churches essential to the story. “Usually we read the script, but in this case it wasn’t necessary,” it explained. “Just the name Dan Brown was enough.”

He does not like novels

You would think anyone who has sold nearly 100m novels worldwide would be a fan of the genre, but Brown steers well clear of fiction, convinced that his reading time could be better spent learning something useful. “One of the reasons I don’t read fiction,” he claims, “is because I can’t really get through it.” Instead, Brown spends his hours in the recliner, reading books on symbols and history. This latter passion has provided him with a spot of bother — soon after publication of The Da Vinci Code, Brown was sued by two authors who claimed he had plagiarised their 1982 nonfiction book, The Holy Blood and the Holy Grail, to create his bestseller. Brown was cleared in an English High Court of all charges and his accusers were left with a multi-million-pound legal bill. In fact, the specific inspiration for The Da Vinci Code came from an art history lecture the author attended in Spain. Brown’s disdain for his chosen genre was not always quite so pronounced, however. His decision to become an author came after reading the Sidney Sheldon potboiler The Doomsday Conspiracy while on holiday and deciding he could do much better. He was also an inveterate childhood fan of the Hardy Boys series, which perhaps explains his fascination with detection.

He may be going bald

Although photographs of Brown depict a man possessing an ample head of blond hair, there is hidden evidence that he may be balding — in 1998, he and his wife released The Bald Book, a humorous look at alopecia. Although the book’s authorship is officially credited to Blythe, sources close to Brown claim he played a significant role in composition, raising questions about just what he has to hide. The couple, writing under the pseudonym “Danielle Brown”, also collaborated on another humour book, 187 Men to Avoid: A Guide for the Romantically Frustrated Woman. Rumour has it that the original title named 188 types of men to avoid, but was trimmed down after protests from Noah.

He used to be a genius

Brown was at one time a member of Mensa International, the organisation of people with high IQs, but let his membership lapse, perhaps after discovering it wasn’t a secret society after all. There is unconfirmed speculation that he was frustrated by the tendency of members to brag about their membership to anyone who would listen.

He is not as rich as JK Rowling

But he is not doing badly. Estimates of his income from Da Vinci Code sales are currently above the $250m mark. Although his earlier work sold only modestly at first, books such as Angels and Demons and Deception Point have also spent quality time on the bestseller lists. Inexplicably, The Bald Book continues to languish.

He likes to hang out

Although little is known about how Brown passes his time at his remote New England redoubt, friends paint a picture of a workaholic who spends long days at his desk interrupted by games of tennis and mind-clearing walks. He also takes frequent breaks to put on the gravity boots he keeps in his office, turning himself into a sort of human ambigram. “Hanging upside down seems to help me solve plot challenges by shifting my entire perspective,” he once claimed.

He has figured out the ultimate code

No, it is not the secret of Christ’s divinity or the true meaning of Masonic ritual, but rather the holiest grail in our contemporary culture: how to create a blockbuster. Brown’s big breakthrough is to understand that most fiction readers these days are really looking for nonfiction books in disguise. If you start with a robust catalogue of fascinating facts and real-life settings, then factor in puzzles, sex, violence and controversy, you unlock the secret of how to print not only books, but also money.

The Lost Symbol is published on September 15