Crossover novels - what a good description for those items of fiction whose intended audience falls between adulthood and young teenagers. Leave the headache of deciding where to place them on the library shelves to the librarians; the reading of them can be done by any who have enjoyed Jacqueline Wilson and have now left her behind, but are not ready for what is generally termed the classics'.

Mind you, there seems to be a certain sort of modern-day realism implied by the term crossover'. Being the next stage up from Jacqueline Wilson, such books tend to be full of all the elements of contemporary life, and most of them not very nice. Black Rabbit Summer by Kevin Brooks (Penguin, £10.99) is a case in point. It's about a long, hot summer and a group of friends enjoying each other's company.

But Swallows and Amazons it is not, for the long, hot summer concerns one long, hot night in particular - old schoolfriends getting together again, and going to the fair. But then two of them disappear (I won't say what happens to the black rabbit), and the situation turns from sour to downright scary and dangerous. This is not what you would call a pleasant read - but crossover it certainly is.

Mothernight by Sarah Stowell (Snow Books, £7.99) is another crossover. It doesn't have the drugs nor the knives, nor the sink estates of Black Rabbit Summer, but it does have a dysfunctional family, an unwelcoming stepmother, a baby's death, a spot of lesbianism, and a friend' whose sole motive in life is cruelty. And it's the reason for baby Alfie's death that is the crux of the story, on which all the relationships hinge.

The action' revolves around 17-year-old Leila, in her last year at school.

She's pretty, clever, at an expensive boarding school, and hasn't been home for years. But now her father invites her and her schoolfriend for the summer holidays.

And now is the time when the past, already ever-present, becomes more pressing, and the truth determines to be out.

Sarah Stowell pulls no punches in this hard story, which is definitely not for younger readers, but is quite gripping, and leaves one wondering how things can get worse.