Though the world Harriet discovers is unquestionably haunted, there is nothing magical about it, or about the furious, lyrical rationality of Tartt's voice. Her book is a ruthlessly precise reckoning of the world as it is -- drab, ugly, scary, inconclusive -- filtered through the bright colors and impossible demands of childhood perception. It grips you like a fairy tale, but denies you the consoling assurance that it's all just make-believe.

Comparisons, in any case, are beside the point. This novel may be a hothouse flower, but like that fatal black tupelo tree, it has ''its own authority, its own darkness.'' ''This was the hallmark of Harriet's touch,'' Hely reflects. ''She could scare the daylights out of you, and you weren't even sure why.'' Harriet's gift is also Tartt's. ''The Little Friend'' might be described as a young-adult novel for grown-ups, since it can carry us back to the breathless state of adolescent literary discovery, when we read to be terrified beyond measure and, through our terror, to try to figure out the world and our place in it.

But this novel is not directly about a murder. It is about the effect that the murder has on the dead boy's family, and especially on his sister Harriet, who was less than a year old when he died, and is 12 when the novel begins. It is through Harriet's desire to come to terms with the past and find her brother's killer that Tartt paints her vision of family life in the American South. As Harriet trudges through one lonely summer, encountering misunderstanding, bereavement, solitude and straightforward cruelty, she drifts further and further into her obsessions. Eventually other, tougher, meaner characters are dragged into her warped world and she is almost destroyed by her attempts to exact pointless revenge on individuals who bear illogical grudges against her.

With its pre-teen sleuths on bicycles, its broad-brush villains and oddly invisible police, The Little Friend courts absurdity time and again. A novel about the force and fraud of children's literature, it shares plenty of improbable conventions with that genre. It also flirts at every stage with kitsch and, in so doing, muddles the categories of "literary" and "popular" fiction even more thoroughly than The Secret History did. Critical puritans (or merely Yankees) will point to its Dixie weakness for verbosity, caricature and melodrama. Yet the verbosity yields passages of mesmerising beauty; the caricature, stretches of delirious comedy; and the melodrama, moments of nerve-shredding excitement.

Southern Gothic is an American literary genre with no British equivalent. It uses lush prose with a strong sense of Southern literary heritage (Faulkner, Flannery O'Connor), is set in the former Confederacy, and features at least three of the following ingredients: insanity, incest, inbreeding, extreme meteorological phenomena, fundamentalist religion, corrupt preachers, slave-owner guilt, black rage, fading gentility, violent white trash, fragrant subtropical plants. At least one main character always dies.
Donna Tartt's second novel, The Little Friend, is a spacious and ambitious example of Southern Gothic.

Like her best-selling 1992 début, "The Secret History," this long-awaited second novel takes the shape of a murder mystery, but it's not really about a death at all. It's about a way of life.

Tartt, who was born in Mississippi, has set her new book in her home state, in a shabby riverside town called Alexandria. From the start, it's clear that the corruptions that interest her most are the familiar ones: ingrained, almost casual racism; hostility between the white-trash "plain people" and the "town folk" like Robin's maternal relatives, the Cleves, with their faded aristocratic pretensions; and—inevitably, in the literature of the South—the stranglehold of the past.