A Week In Books: Join the generation-jumping party

In fiction, every pundit now seems to accept that youth is the new maturity. With both the adult and children's paperbacks of Mark Haddon's The Curious Incident... high in the charts, the "crossover" cult has picked up more devotees. And the vogue for novels with an appeal that spans the ages has now seized the prize-givers as well. In this year's Carnegie Medal shortlist, crossover titles dominate the contest for Britain's most august award in children's literature.

Haddon features on the list, of course, along with such "mature" reads as Private Peaceful, the First World War novel by the Children's Laureate Michael Morpurgo, and The Fire-Eaters by David Almond: his story of a North-eastern childhood during the Cuban Missile Crisis. Other Carnegie candidates that grown-ups might read happily on bus or train include Linda Newbery's Sisterland, which rediscovers the plight of child refugees from Nazi Germany, and A Gathering Light by Jennifer Donnelly. This book appeared first as a children's hardback, but its success prompted Bloomsbury to issue a crossover paperback.

Colin Brabazon, who chairs the Carnegie panel, says that the rise of crossover publishing has "alerted adult readers to the sophistication of books for children and young people". The judges of the Jewish Quarterly/Wingate Literary Award agree. Yesterday, they gave this year's fiction prize to David Grossman's Someone to Run With, the Israeli novelist's tale of friendship and survival among the street kids of Jerusalem.

I have no desire to spoil this cosy generation-jumping party. The finest current fiction for young readers does, indeed, exhibit a scope, skill and seriousness that leaves much adult writing trailing in its wake. At the same time, we may be in danger of losing the distinction - in literary terms - between the alcopop and the dry martini. Not only will adult fiction proper always need to call on its own special repertoire of pleasures and perceptions. Even adult novels about children may sometimes draw on subjects and emotions that lie beyond the reach of crossover yarns.

Take the new novel by Adam Zameenzad: Pepsi and Maria (Maia Press, £8.99). In this curious and intriguing performance, two clever but vulnerable street kids (them again) in a nameless Latin American country outwit a brutal cop, a sleazy politician's clan, and the assorted thugs and creeps they meet while searching for the shanty-town atop a garbage-heap that Maria once called home. With its witchy flights into Native American magic, its near-cartoonish villains and helpers, its short, action-driven chapters and dynamic, concrete language (and, of course, that gritty Third World setting), it often reads like a fashionable work of contemporary teen fiction.

Yet this is definitely not a children's novel; or rather, it feels much like an adult adventure composed as a pastiche of teenage literature. Zameenzad deals matter-of-factly - but never salaciously - with the pitfalls of sex and drugs his kids have to avoid every day. And he explores the cruelty and corruption of the pursuing adults in a way that might baffle or upset younger readers. Innocence and depravity converge in unsettling intimacy. At one moment, Maria returns to her trash-mountain home and finds her little dog wagging its tail; at the next, the bullying cop's turmoil explodes in a gruesome orgy of violence.

It all adds up to a wildly uneven ride, although the breakneck pace of the action and the sparkling colours of the background make up for the lurches and jolts. If you can imagine a hybrid of City of God and The Wizard of Oz, then Pepsi and Maria comes close. And that, in its own weird way, must count as a crossover triumph of sorts.