After 'The Da Vinci Code' come the Da Vinci clones

The best-selling church conspiracy thriller has spawned a whole new genre as publishers seek to emulate its success

It has already sold 18 million copies, spawned a mini-tourist industry and put the Roman Catholic Church on the back foot. But if you thought Da Vinci Code fever might at last be on the wane, think again because publishing analysts are warning there is much more to come.

It has already sold 18 million copies, spawned a mini-tourist industry and put the Roman Catholic Church on the back foot. But if you thought Da Vinci Code fever might at last be on the wane, think again because publishing analysts are warning there is much more to come.

Dan Brown's blockbuster has been so influential it has created its own literary genre, say major book chains, which are seeing a rising flood of new thrillers based on historical mysteries. American historians, international conspiracies and religious maniacs abound.

The "Da Vinci clones" include the best-selling The Rule of Four by Ian Caldwell and Dustin Thomason and The Assassini by Thomas Gifford, in which an age-old brotherhood of killers is thought to be behind the death of a troublesome nun. In Robert Finn's Adept, described as "The British Da Vinci Code" by the Borders bookchain, an antiquities expert grapples with an ancient secret and a ruthless killer.

American bookshops are stocking The Third Translation by Matt Bondurant, which features one of the last great hieroglyphic mysteries, and Map of Bones, by James Rollins, expected here soon, based on a hunt for the remains of the Magi.

Even the up-market Hamish Hamilton imprint, a division of Penguin more used to dealing with Paul Theroux and Zadie Smith, has got in on the act with The Geographer's Library. Simon Prosser, publishing director of Hamilton, said the book was written well before The Da Vinci Code first appeared. However, he said: "If the association means we get more copies into the shops, then we're not unhappy."

The success of The Da Vinci Code has been extraordinary, partly because of the multi-million-pound trade in spin-offs. At the last count there were 70 different guides and "de-coding" manuals. In April, Time Warner publishes The Asti Spumante Code: A Parody by Toby Clements, and in May filming starts on a movie of The Da Vinci Code starring Tom Hanks. Churches featured in the book, from St-Sulpice in Paris to the Temple Church in London, have been astonished to find streams of new visitors clutching copies.

It has also persuaded new readers into the bookshops. Recent research by The Bookseller magazine showed that more than a third of UK adults never buy books. Joel Rickett, its deputy editor, said: "The Da Vinci Code has shown the scale of the possible market. You can reach millions more people than the industry has been reaching for the past few years."

The Da Vinci Code has also become the first book ever to have an archbishop dedicated to criticising its contents.

Cardinal Tarcisio Bertone, the Archbishop of Genoa and a possible successor to the Pope, has been appointed by the Vatican to rebut the novel's "unfounded errors".

The book has earned its author an estimated £140m and, last week, the German firm Bertelsmann, which owns Brown's publishers, posted a 30 per cent rise in profits.

The Da Vinci Code (Dan Brown)

Following a murder at the Louvre, a code expert discovers clues in the works of Leonardo showing that Jesus married Mary Magdalene, had a child, and that the Holy Grail was not a chalice but his bloodline.

Conspiracy rating: 5

The sales figures speak for themselves.

Is now pursued by ...

The Rule of Four (Ian Caldwell and Dustin Thomason)

One of the biggest hits of the year so far. Two Princeton academics try to unravel the mysteries of an ancient coded manuscript, The Hypnerotomachia Poliphili (The Strife of Love in a Dream). Violent deaths included.

Conspiracy rating: 4

Manuscript facsimiles are also selling well

The Historian (Elizabeth Kostova)

"A young girl discovers an ancient and disturbing book in her father's library, which opens a dark chapter in his past." She searches out the truth about Vlad the Impaler, the medieval ruler of Transylvania and basis for the Dracula legend.

Conspiracy rating: 4

Contains plenty of sinister historical fact

The Geographer's Library (Jon Fasman)

A reporter delves into the death of a professor and gets involved with alchemy and a search for 14 cursed talismans. It promises to "meld the ancient legends of alchemy with the plot of a pacy thriller" when it arrives next month.

Conspiracy rating: 3

Will take the Da Vinci format to a more literary crowd

Map of Bones (James Rollins)

Former members of the US special forces search for the bones of the biblical Three Kings, which have been stolen from a German cathedral. It is said to be already selling well in the United States.

Conspiracy rating: 3

Described as Raiders of the Lost Ark meets The Da Vinci Code