ONE of the few success stories on the high street in recent years has been that of Waterstones. From debts of £130 million and possible closure in 2013, the chain returned to profit last year.

The spring in the book chain’s step can be seen in Salisbury with its revived programme of author events, which this week features the award-winning children’s author, Frances Hardinge.

Hardinge is one of those wonderful writers who eschews easy definition. When I caught up with her this week, she explained that her pitches to her publisher tended to begin with, “Look, I know this is going to sound a bit mad, but hear me out…”

In 2015, she became the first children’s author to win the overall Costa Book Award since Philip Pullman in 2001. Like Pullman, her writing is rich and complex enough to satisfy readers of all ages.

Her novels mix history and the supernatural into a blend all of her own and her new book, A Skinful of Shadows, is no exception.

I asked her where this particular idea came from. “One idea that had been lurking in my mind was the notion of a ghost bear,” she told me. “I happened to learn a little about the historical mistreatment of dancing bears, and it made me rather angry. So I imagined one of these abused bears coming back in spectral form, unshackled at last and in search of vengeance.”

Frances set her new novel during the Civil War because “I’m always fascinated by times of change, rebellion and aftermath, and this particular period fitted the story I wanted to tell.” She is clearly a writer who likes her research, describing it as ‘a lot like treasure hunting’.

Among her research into the period, she learned about spies hiding messages in eggs, how artichoke juice was used as invisible ink, and the process of ‘letter-locking’ – folding and tying letters in such a way that anyone trying to sneak a look would rip them.

As part of the Waterstones event, there will be a guided ghost tour around Salisbury led by Timezone Tours. I asked Frances where her interest in the supernatural came from. “I always write for the younger version of me,” she explained, “and younger me was quite an odd little girl. I was always fascinated by dark tales where the familiar, safe world might peel back to show something weirder and more dangerous.”

I wondered whether she believed in ghosts herself. “I like to keep an open mind,” she said, adding that, “fortunately, I don’t need to believe in ghosts to find ghost walks totally fascinating…”

Frances Hardinge is at Waterstones Salisbury on Thursday, May 10 at 6pm. Tickets £10.