Imagination may be a writer’s most precious tool, but when it comes to historical novels, it can only take you so far. Having written three books set in the present day, Maggie O’Farrell journeyed back in time for her fourth, The Vanishing Act of Esme Lennox. A heartbreaking tale of a young girl misdiagnosed with mental illness and institutionalised for most of her life, O’Farrell’s latest work takes us from 1930s India to modern day Edinburgh.

‘It’s the first book I’ve done a lot of research for, because it was set in the past,’ she says. ‘And I also had to learn a lot about psychiatry, which I really enjoyed. The tricky thing about research though, is you read all this interesting stuff, then you have to decide how much to throw away.’ O’Farrell admits to finding the research process harrowing at times, in particular speaking to women of Esme’s generation. And when it came to her central character’s supposed ‘illness’, there was no need to make anything up. ‘Everything in the book – all the circumstances on Esme’s admission forms – were taken from real documents and case studies. I was quite sure I wanted to do that, because the truth is horrifying enough, you don’t need to embellish it at all.’

Serving as a counterbalance to Esme is her great niece, Iris, an independent young woman with a similar penchant for waywardness. And while things have clearly improved, O’Farrell shows that disapproval of such women continues. ‘I’ve always been interested in what happens to the same type of woman at different times in history; an uncompromising girl who people label as difficult because she’s not willing to conform to what society expects of her.’ (Kelly Apter)

16 Aug (with Tracy Chevalier), 7pm, £8 (£6).