When Bookouture asked me for some more novel ideas, a story about a pair of half-sisters popped into my head. I have no idea why – I don’t have a sister and have no experience of how that relationship works. Apart from Louise Jensen’s enthralling The Sister, which I’d already devoured, I decided not to read any other sister books until I’d finished mine – The Good Sister (out August 16). Since then, I’ve read several and have been fascinated by the variety of approaches taken by their authors. It started me thinking, what is it about the sister relationship that is so interesting to writers and readers?

Clearly, sister books are ‘on trend’. As book blogger @tk2everywhere noted in a recent review of The Good Sister: “Good sisters, bad sisters, little sisters, big sisters, there are sisters all over the place; it’s clearly a subject which strikes a chord with people.” Sister, Sister (Sue Fortin), My Sister and Other Liars (Ruth Dugdall), Two Sisters (Kerry Wilkinson) and The Roanoke Girls (Amy Engel) are among the books I’ve recently read. In The Good Sister, I explore the theme of ‘nature versus nurture’, taking two half-sisters who have grown up believing they were the only child of their beloved father, now dead. At first, their shared parentage unites them, but jealousies and rivalries soon bubble to the surface with disastrous consequences.

A short while ago, readers were captivated by stories of dark, corrupted marriages – Gone Girl (Gillian Flynn), I Let you Go (Clare Mackintosh) and The Girl on the Train (Paula Hawkins) being some of the most obvious examples. Maybe we’ve simply moved on to other relationships in the Domestic Noir arena. And because so many writers and readers in this genre are women, it make sense that sisters take centre stage, rather than brothers. As crime blogger @northernlass73 says: ‘It’s a complex relationship. It can easily be one of love or hate. You go through so much with siblings and have different perceptions.’

In the crime genre, the sister relationship offers endless opportunities to present strong, active female characters fighting on an even battlefield. Perhaps this sits more easily with writers who, like me, are uncomfortable with stories in which men are almost always the villains and women the helpless victims. Last year’s ‘Killer Women’ festival debated the issue of whether crime literature is misogynistic and I wonder if perhaps the new wave of ‘sister crime’ is a subtle response to this.

Nancy Berone mines this rich vein in her latest mystery thriller, Lullaby for my Sister (Happy Publication Day, Nancy!). She says: “Sister relationships can be so varied, so dynamic! One day you’d give a kidney, and the next you’re not talking to each other for some dumb reason. The swing of possibilities in a sister-sister relationship is so wide, anything can – and will- happen. Lullaby for my Sister is like that – even the littlest things can overthrow a relationship both ways, when people have been hurt and there’s a lot of forgiving to do.”

This sister preoccupation extends well beyond the crime/thriller genre into women’s fiction – Renita d’Silva’s novel, A Sister’s Promise being an excellent example. Set against the dramatic backdrop of India, A Sister’s Promise is a powerful, emotional tale of family secrets, love and the ties that bind sisters together. As Renita explains: “I am entranced by the bond of intense love warring with competition and irritation between siblings, how families bring out the best and worst in a person. I think when we are with the people we grew up with, we automatically revert back to the children we once were, bypassing all the growing up we have done in between, and that makes for some very fraught relationships as old feuds and resentments flare.”

In other words, sisters automatically give the writer everything needed to create the conflict, drama and emotional intensity that is at the heart of every great story. Of course, this is not a new discovery. Louisa May Alcott’s Little Women being probably the best example of a wonderful book about sisterhood. Then there’s the nation’s favourite novel – Pride and Prejudice, which follows Elizabeth Bennet and her four sisters, all with very different personalities, who are searching to find their place in the world. Even the fairy tale classic Cinderella explores a difficult relationship between step-sisters. So, while the sister publishing trend may soon be replaced with another, this sibling relationship will no doubt continue to intrigue us for centuries to come.

Do you have any favourite books about sisters? If so, please share them below, via Twitter – @jessryderauthor or my Facebook Page – JessRyderAuthor.  If you would like to read The Good Sister it’s available for pre-order now, publication date 16 August 2017.