Sharper Than a Serpent’s Tooth : A THOUSAND ACRES, <i> By Jane Smiley (Alfred A. Knopf: $23; 371 pp.)</i>

A problem novel is a problem. If it is a detective story, say, or an exposure of conditions in the Chicago stockyards, we take it on its own singleminded level--solving the mystery or learning about the conditions. It needs to be lucidly and enthrallingly expounded; apart from that, we are simply grateful for whatever adornments of style or character may be thrown in.

When it is a full-fledged work of fiction, though, we feel two currents tug against each other. There is the whirlpool vortex--find the problem, explore it, elucidate it--and the freer, more complex, less foreseen tides that fiction sets going in its interplay of character, story, setting and the writer’s voice.

Paradoxically, if Jane Smiley were a narrower and less gifted writer, her new novel might have worked better. The “problem� in “A Thousand Acres� is current and troubling: the disabling consequences of parental sexual abuse, and of the family denial that turns a knife thrust into a deadly infection. She sets it in a sprawling hybrid framework that is partly a rigorous psychological study, partly a deliberately lurid melodrama, and partly the subtle and affecting evocation of a family and a place. It cannot hold together.

The melodrama, employed with a touch of satire and to make a point, is a detailed reworking of “King Lear.� It is a reversal, in fact, “Lear� told from the point of view of Goneril and Regan, with Lear the terrible old man they accused him of being, and they themselves terribly damaged, and fighting to survive.

Lawrence Cook, a hard, tempestuous farmer, is a petty monarch. He works 1,000 acres of prime Iowa land, having built his holdings partly by inheritance, partly by driving energy, and partly by taking advantage of neighbors forced to sell out. His two oldest daughters, Ginny--the narrator--and Rose, and their husbands Pete and Ty, work and keep house on the Cook lands under their father’s increasingly paranoid eye. Caroline, the youngest, has gone off to be a lawyer in Des Moines.

Suddenly, Lawrence announces he will retire and divide his property among his daughters. Rose and Ginny accept--Lawrence is cranky and failing, and their husbands are capable and deserve their chance--but Caroline demurs. In a rage, Lawrence casts her out.

Land and power gone, the old man turns erratic. He goes on foolish shopping sprees, he drinks heavily and smashes up his car. When Ginny and Rose insist he give up driving and get some exercise, he curses them and runs out, as it happens, into a fearful rainstorm. Before long, having sheltered with an old, equally paranoid neighbor and buddy, he is suing Ginny and Rose. He is joined in the suit by Caroline, who now returns to back up a father she never had much to do with, and whom she chooses to regard as wronged by greedy sisters.

“Lear� then, or rather, anti-Lear, down to having Lawrence’s neighbor-buddy (Gloucester) blinded in an accident; making Ginny’s easygoing husband, Ty (Albany), feel that she has been unnecessarily confrontational; and even having Ginny and Rose quarrel over a lover.

All this sits ludicrously upon the Iowa countryside, and Smiley is in no way a ludicrous writer. She is sending a signal, she is parodying her melodrama even as she uses it for a purpose. Ginny--a conscientious housekeeper--carefully grinds up river hemlock in her home-canned sausage and deposits it in Rose’s larder. “I waited for Rose to die,� she tells us, “but the weather was warm for sauerkraut and sausage; that was a winter dish.�

The serious purpose behind this comic grisliness, of course, is to convey the wild dysfunction of abuse and concealment. Ginny has lived all her life placating, holding things together, denying her pain. For a long time, she can’t even remember it. Rose, remembering every one of the 200 times that Lawrence came to her bed when she was a teen-ager, keeps silent, but she grows up to be irascible and disruptive.

What if, Smiley is asking; what if Lear were the abuser and what if his two oldest daughters were simply asserting themselves and trying to break free? The victim is blamed; the victim blames herself.

It is timely, ingenious, devastating, as a problem rigorously ventilated and as a parodic theatrical reversal used to dramatize it. But these machineries get out of control; they chew each other up. Particularly do they weaken the broader novel of character and place to which they are attached.

Smiley makes a living, breathing portrait of the Iowa landscape, so peaceable and orderly but maintained in brutal tension. In a few introductory pages, we get a bucolic picture of three neighboring farms as Ginny recalls them from her childhood. There was her family’s, the Ericson place, where she and her sisters would go play, and the farm belonging to Harold Clark, Lawrence’s buddy. Then she gives figures, and the peace turns baleful: Cook, 640 acres, no mortgage; Clark, 500 acres, no mortgage; Ericson, 370 acres, mortgage.

“Harold Clark and my father used to argue at our kitchen table about who should get the Ericson land when they finally lost their mortgage,� she writes. It is the secret behind the picture postcard; when she resumes the narrative, now grown up and married, her father has won the argument and the land. Of that rich landscape, drained from marsh and floating on its water table, she tells us: “The stationary fields are always flowing towards one farmer and away from another.�

It is Ginny’s voice that relates the seemingly golden family life that the marsh will rise to flood. It is a devoted, troubled voice; a voice that clings to the positive, that resists confrontation for as long as it can. It is supple and witty, and it evokes the lives around her in all their tensions, troubles and pleasures. It is the voice, of course, of denial; yet it has created a complex fictional life. When it is turned to spinning the anti-Lear melodrama, to relating and taking part in the self-investigation and its violent consequences, it goes flat. It becomes more truthful--nothing is hidden--but less alive.

It is, again, the problem with problem fiction. In life, we may try to confront our pasts, to overcome our denials, to remove the shadows that impede us. But fiction is not therapy. It is partly the shadows that bring characters up into relief. Lighting them without flattening the characters is a complex process. Ginny is more interesting and individual when she is denying. Before the Cook family secrets are vented and their disastrous consequences endured, she is a person; afterwards, she is mainly a solution, though Smiley never suggests that it is a happy one.