Cressida Cowell | 'I wonder that there's a whole section of the population we're not reaching'

Cressida Cowell | 'I wonder that there's a whole section of the population we're not reaching'

"It was emotional and complicated," says Cressida Cowell of saying goodbye to her hit series How to Train Your Dragon (HTTYD). The series débuted as Cowell's eldest daughter was born and concluded as she left home; the experiences of her own childhood and bringing up her children are woven into the story. But even as she planned the final HTTYD books, new ideas were brewing.

The challenge was to pinpoint "something I cared about as much as Hiccup's world" with the rather daunting knowledge that "everyone would be watching". When I meet Cowell at her London home she shares with me the genesis of The Wizards of Once (Hodder Children's, September), an outsize "ideas" book overflowing with illustrations, character studies, poems and notes."I started working on this five or six years ago," she explains, and the very first sketch is that of a witch's feather, a pivotal object in the story. At this stage she works in pencil, which enables her "to feel my way more organically into that world", adding plot and structure later. It's a real visual treat, words and pictures intrinsically linked.

In The Wizards of Once, Cowell looks to the dawn of the Iron Age, plunging us into the wildwoods of ancient Britain, a richly imagined world of sprites, snowcats, fairies, ogrebreaths and wizards, warriors and magic. It's the story of a boy wizard and a girl warrior from warring tribes, and what happens when their worlds unexpectedly collide. Enormously entertaining and satisfying, it's narrated and illustrated with tangible energy and verve. The fantasy world and quest-driven plot are a triumph, and Cowell skilfully engages readers to think big: our two heroes grapple with timeless concerns of identity and parental approval, how to find courage, hope and perseverance, and what the consequences of their actions can mean. The scratchy character portraits and scenes scattered through the text have an evocative magic of their own.

The HTTYD series was inspired by Cowell's summers on a Scottish island and The Wizards of Once is also borne out of the places of her childhood, this time West Sussex, where her grandmother lived. An Iron Age hill-fort, Trundle Hill, was within biking distance, a strange, enchanting landscape where magic seemed all too possible. "You feel like you're on top of the world when you're up there. It's no wonder that people used to imagine giants had made these earthworks and barrows." Her childhood reading also echoes around the pages: The Wizard of Earthsea, Diana Wynne Jones, Tolkien, books rooted in landscape and crackling with magic. "One of the reasons that children find magic so exciting is that they get told what to do all the time. It offers them a freedom and power." Her creatures of folklore are drawn with a distinctive Cowell twist. "I did lots of fairy, witch and giant research... It makes the fantasy more rich. Bringing in Arthurian and Shakespearean references, it's very British-inspired." Her writing shed is piled with her research, from Arthur Rackham, who influenced her spiky, playful sprites; to Robert MacFarlane's nature writing. "Nature is a lot of what these books are about. The lack of unsupervised access to landscape is something that worries me."

But behind the magic, it's empathy that lies at the very heart of The Wizards of Once. It's ultimately the story of two children who have been trained to hate one another from birth, and how they address this. Cowell is passionate about "the ability of books to make you see things from another point of view", and sees fantasy as a great medium for exploring big ideas. Bullying and the pressure to conform, both big concerns in Cowell's postbag, will also feature, along with the idea of what adults can learn from children.

Cowell studied English at Oxford and briefly worked in publishing before realising her true passion was on the creative side, going on to study illustration at Central St Martins and Brighton University. Success didn't happen overnight and she was soon juggling a new baby and part-time work alongside her writing. "There was a lot of pep-talking through my twenties, but I had a fire in my belly to make it work." Hodder published picture book Little Bo Peep's Library Book in 1998, and the first HTTYD novel in 2003. Although the book "picked up a loyal fanbase" and strong rights sales, it was not an instant blockbuster, something Cowell is keen to stress to young fans. HTTYD was signed as a trilogy but she always knew it had a longer story arc, recognising the power of series to hook children into the magic of reading. "If they know the world, they know it's worth that effort they need to make."

For Cowell, who has been an ambassador for the National Literacy Trust (NLT) for over a decade, getting children reading is part of the job; "buckets" of school visits and festival appearances are key and "so inspiring and invigorating". Books, she feels, "offer something special and different. A language medium, a thought medium, a thinking space. And it's also fantastic for empathy. On a screen it happens out there, in a book it happens in your head." She has the utmost respect for her readers and never dumbs down.

"I do put in complicated ideas because I think children are highly intelligent. Thinking outside the box is natural to them. The heroes of my books are always the creative, inventive thinkers." She uses the rather lovely analogy that she wants her books to "feel like sweets rather than brussels sprouts. Not something that you ought to be doing but something you want to be doing," paying close attention to "the way the stories are told, the way they're presented visually, the rhythm and the pacing." Something that really strikes me about her writing is how well-tuned it is to being read aloud, and this is a conscious effort. "I want parents to read with children beyond the age when they can read for themselves." Seeing adults respond to reading with laughter or tears "sends a really important message that books have a power". The closure of school libraries dismays her. "I wonder that there's a whole section of the population we're not reaching," she says, but cites initiatives like the NLT's work with the Premier League as a positive step. She’s thrilled to become the first Foyles Literacy Ambassador this summer, and will work with the chain on events, recommendations and a creative writing competition.

A third HTTYD film will be released in 2018, and DreamWorks has snapped up film rights to The Wizards of Once. "I've been so lucky," she says of the films, crediting their "incredible power" to bring children from non-reading families to books. But for now she's deep in the writing of the second The Wizards of Once book. She's firm that this one will remain a trilogy, though I sense her energy for this world could easily spill into futher volumes. "It's difficult," she admits, "but I still have so many other stories I want to tell."