Child of My Heart by Alice McDermott

Alice McDermott, author of the prizewinning Charming Billy, has an interest in characters as charismatic as they are disturbing. In her new novel, we meet Theresa - a teenage girl who controls her small but volatile world with the cheerful efficiency and casual force of a girl scout-cum-goddess.

Those around Theresa do treat her like something of a deity: her awed parents, her sickly cousin, the lonely children she babysits for as well as their cynical mothers, lustful fathers and motley dogs and cats. Theresa is coolly aware of her worth but appraises herself and everything else with the "precise and indifferent observation of a creature very much in the world but not yet of it".

Theresa can describe what is going on but not entirely what it might mean. Her detachment is a kind of incomprehension which acts as a shield but sometimes as a blindfold, too. She takes risks, not just with herself, and proves as capable of catastrophic misjudgement as any other adolescent.

She is the only child of a couple who moved out of the city to a fisherman's cottage on Long Island because rich people lived there and placing Theresa among them was "their equivalent of offering me every opportunity". Sure enough, she is taken up by several local families, who come to depend on her to an unhealthy degree. These range from the Morans, a rag-tag of neglected children who fetch up on her doorstep each morning to the childless anglophile tweedy Richardsons, who have two Scottie dogs which Theresa walks each day.

However much adults may admire or desire her, they do not enjoy the way her presence confronts them with the loss of their own youth. It doesn't help that Theresa has a ruthless eye for the details of ageing. When an old drunk passes out on the lawn, she gets a glimpse of "a mound of pale adult backside, as gray and lonesome as a sand dune in winter". Theresa knows already that what counts is the one thing that cannot be cosmetically restored, the quality of flesh.

Theresa's main project is her eight-year-old cousin Daisy, a skinny redhead who is mottled with bruises but spirited enough to insist on wearing her jewelled plastic shoes to the beach. Theresa is too sure of herself in looking after the child to face up to her most urgent need and in this McDermott gives Theresa enough grown-up vanity to make her possible and likeable.

Child of My Heart is written in Theresa's voice, in retrospect, and makes the best possible use of its simultaneous adult and child perspectives, and a wonderful formality which clarifies rather than distances us from what she describes. We get to enjoy her acuity while being able to see through it. We appreciate her thoughtfulness and calm, but watch the shadow looming behind.

The book is haunted at just the right vague level for us to be unsettled enough not to think that we know better and for us to wonder, just a bit, if the worst of our fears for Theresa and her brood might have come true. Like adolescents, we glimpse and overhear enough to undermine the version of events we have been given. What are the Kaufmans doing behind closed doors when Theresa hears them calling "Oh, where is it? Oh, what happened? But in a language I don't know." Child of My Heart is a remarkably poised and provocative work.

Lavinia Greenlaw's novel, 'Mary George of Allnorthover', is published by Flamingo