CRESSIDA COWELL, the new star of children’s fiction, has arrived without any of the fanfare and hype that, post-Harry Potter, has become a commonplace of the market. Three years ago she published How to Train Your Dragon, a novel for 7 to 11-year-olds that sold 100,000 copies by word of mouth. It has been bought by Dreamworks Animation, the studio that brought us Shrek, and is due for release in 2009.

Irresistibly funny, exciting and endearing, How to Train Your Dragon tells the tale of Hiccup the Useless, a nerdy Viking boy whose gigantic father Stoick the Vast is chief of the Hairy Hooligan tribe living on the Isle of Berk. Despised by the other Vikings, Hiccup is even more wretched when he picks a runty, remorselessly selfish dragon, Toothless, to be his hunting beast. Little does he know that this is how he will become a dragon whisperer, something that will save his tribe when the monstrous Green Death rises from the seabed. Two more equally wonderful Hiccup adventures have followed, and How to Speak Dragonese is out this month.

Hiccup’s adventures were inspired by Cowell’s memories of her family holidays on a tiny island in the Inner Hebrides, bought by her father. Cressida, her sister and her younger brother Caspar were taken off to camp on an island that was “just rock and heather”, cut off from the outside world but surrounded by an archipelago of other tiny, uninhabited islands.

“It was a child-sized world which an imaginative child would find easy to imagine other different tribes living on,” she says. Her young parents did the kind of mad things all too familiar to the Hairy Hooligans, taking the children out sailing in storms. You know immediately you read Cowell’s books that the author has experienced what real cold, fear and peril is like.

“It was the kind of place where you might expect to see dragons sailing overhead,” she says. Now a pretty, bespectacled mother of charm and intelligence, she realised as a child that she “might be a different species” from her adored father when holding him by the ankles as he hung upside down from a cliff to spy on a nest of buzzards.

Back in London, she drew endless archipelagos at St Paul’s School, becoming obsessed by Vikings and the Dark Ages after inspiring history lessons from an American teacher, Miss Macdonald. Later, despite her love of art leading to a transfer to Marlborough, Cowell read English at Oxford before going to both Central St Martins College of Art and Design and Bristol, where her first book was accepted by Hodder while she was doing a course in narrative illustration. Eight picture books followed before Hiccup the Viking Who Was Sea-Sick showed her a way of making the jump into novels.

The madly funny pictures of Vikings, monsters, raging seas and battles with which her texts are lavished are part of the reason children adore her books. Like Ronald Searle, Cowell has a wit of line that conceals a penetrating intelligence about how mean and calculating people can be.

Yet Hiccup is also inspired by something closer to home, which explains its success with reluctant readers (especially boys). Her brother Caspar had a miserable time at public school. He was dismissed academically and nobody discovered how intelligent he was until he went to university in America, topping a PhD at Princeton with a job as Professor of Philosophy at MIT. In academic terms, he made the journey that Hiccup is now making to become the Last Viking Hero, whose adventures ( “translated from Old Norse”) strike a deep chord in any child who has ever felt intimidated by teachers, peers or indeed parents.

“All boys have this transition to make from little boy into something that to them looks like the Incredible Hulk, with this big body and deep voice,” says Cowell, who has two young daughters and a baby son by her husband, a director of Save the Children.

“I try to write from both Hiccup and Stoick’s point of view, because as a parent I understand it’s hard for Stoick to realise that his child is different. It’s an awkward moment when you realise that love is not just narcissistic. When my daughter Clemmie said that her favourite subjects at school were sports and mathematics, she suddenly felt very alien.”

It was with Caspar in mind that she began to write the Hiccup books at her house in Chiswick, using not only maps, lists, songs, report cards, blots and drawings, but mixed-up typefaces, important in keeping a reluctant reader’s attention. Dragons speak in wobbly Gothic; Stoick in capital letters; Romans in Romanesque. Like Cowell’s friend, the children’s author Lauren Child, she uses typography as an art in itself; the audiobooks, brilliantly read by the new Dr Who, David Tennant, capture these shifts of voice and tone.

Though it looks as if it is thrown off, each book goes through 15 drafts and is a work of sophistication. Each builds on the success of the last, both in terms of sales and of an increasingly rich imaginative world in which ancient Rome has now made an attempt at invasion, only to be beaten off by Hiccup’s genius and the help of tiny, ferocious nanodragons. It’s easy to see why Dreamworks thinks that it will make a great animated film, for like Shrek, Cowell ’s books have struck the balance between traditional fairytale thrills and Post-Modern comedy.

But it is the idea of having your own small dragon (“I used to long for one as a child; it’d be the coolest pet in the world”) that most appeals. Her father’s obsession with birds of prey is translated into a series of Top Trumps spoofs that solemnly describe different breeds of dragon, and their “fear or fight factor”. Toothless is a “Common or Garden Daydream”, despised by big, sneering Monstrous Nightmares. Yet Toothless becomes Hiccup’s unreliable ally once our hero realises that the Viking advice to SHOUT AT THEM might be less successful than learning to speak Dragonese.

“I like a story with a moral, and I like making readers think,” Cowell says. “The bit in How to Train Your Dragon when Hiccup is talking to the Green Death is actually quite philosophical.”

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