IN THE Nightwalker by Sebastian Fitzek (Sphere, £8.99) German architect Leon wakes one morning to find his wife packing her bags to leave him.

Her face is bruised, her manner fearful, and Leon can only suppose that the sleepwalking which plagued his youth has come back, worse than ever before.

But as he struggles to understand what he’s been doing in his sleep, and where his wife has gone, he learns that the difference between asleep and awake may not always be knowable or even meaningful.

This is a fabulously bizarre psychological thriller, probably not to be examined too closely, but full of wild twists and apparent impossibilities which are all explained in the end.

Auntie Poldi and the Sicilian Lions by Mario Giordano (Bitter Lemon, £8.99) is the charming opening to a new amateur sleuth series.

Poldi is a 60-year-old Bavarian who moves to Sicily with the intention, her family fear, of drinking herself to death while enjoying a sea view.

Widowed and reluctantly retired from her job as a TV costume designer, she’s depressed. There seems to be little to prevent her from achieving her morbid ambition until a local handyman vanishes.

Frustrated by police inaction, while rather fancying the cop in charge, Poldi — daughter of a homicide detective — sets out to solve the mystery. She must do so without mentioning the mafia, which everyone is keen to inform her is merely “an invention of those fascists in the north.”

The plot is secondary to the food, culture and history of Sicily and to the delightfully fresh creation of Poldi herself.

It says something about the world we currently live in that it feels somewhat startling to read a novel featuring a sexually active middle-aged woman.

In The Loving Husband by Christobel Kent (Sphere, £7.99), Fran leaves her job at a magazine in London and moves to a lonely farmhouse on the edge of the Fens with her husband, Nathan, and two young children.

For Nathan it’s a return to the landscape of his childhood, while Fran hopes it’s a chance to rebuild a marriage which only she knows is in trouble.

But when he’s murdered, she becomes the main suspect — especially as the police uncover the secrets that both husband and wife have been assiduously keeping from each other.

With a denouement taken from recent headlines, this is a riveting, albeit relentlessly sombre, mystery in which the male characters are all loathsome and the women aren’t much better.

If you’re looking for a perfect summer holiday read, pick up Another One Goes Tonight by Peter Lovesey (Sphere, £19.99).

In the latest in this long-running series Peter Diamond, head of Bath CID, saves a man’s life by administering CPR after a traffic accident.

While the eccentric victim — a railway enthusiast who rides around town on an electric tricycle — lies in a coma, Diamond’s investigation reveals the awful possibility that he might have rescued a monster.

Marvellous misdirection crowns a cunning story, told with gentle humour.