Stolen Child, Idiot Thief : VANISHED <i> by Mary McGarry Morris (Viking: $16.95; 222 pp.) </i>

The white that flares out of a woodblock print is not the absence of the engraver’s tool but its deepest scoring. And to personify fiction’s equivalent whiteness--a simple soul or holy fool--requires a most intense and sharply worked kind of characterization.

Dostoevsky’s Prince Myshkin is not simply the space between the agonized convolutions of “The Idiot’s” other residents. He is a series of layered strokes and interventions. He is a feverishly active agent of heroic peace, a brilliantly colored whiteness. Forget about “angelic” referring to a beatific smile--it refers to beating wings.

Mary McGarry Morris has organized the desperation and backwoods horrors of her first novel around a “white character,” a soul who is simple to the point of retardation.

He is affecting, to a degree; and to a degree, he serves the author’s purpose of giving shape to the near-Gothic atrocities of her story. Ultimately, though, he is an empty space. His radiance comes less from himself than from the contrast with the tormented and terrible people around him.

Aubie Wallace is gentle, passive and quite unable to refuse anything that people ask of him. As a child in an institution, he made no objection when fitted by mistake with a brace intended for another boy; he was crippled as a result. Grown up, he does odd jobs in a ramshackle rural settlement in Vermont.

When Hyacinth, plain and a spinster, decides he is all she can get, she marries him. He gives her two moronic sons and unquestioning obedience. Then Dotty comes along.

She is a teen-ager who has run away from home after killing her father, who had regularly been forcing sex upon her. Encountering Aubie and his father-in-law’s truck, she literally steals both. Not long afterward, when Aubie shows signs of wanting to return home, Dotty steals a baby and forces Aubie to stay with her on the run.

So much is prologue; the story itself begins five years later. They have become itinerants, traveling around the country with the child, Canny, and supporting themselves with flea-marketing, a little prostitution, and occasional small larcenies.

Dotty, fierce and restless, is fed up. She wants to abandon Canny and move on. Aubie, who cherishes the child, doesn’t actually oppose Dotty’s various schemes, but his passivity manages to sabotage them.

It is an odd trio. Dotty, in effect, is the man of the family, burning to rid herself of her burdens but not quite able to. Aubie is the child. And Canny, only 7, is maternal and placating.

Up to this point, Morris finds an intriguing equilibrium for these assorted elements. There is a perilous wildness in Dotty’s conjoined ferocity and compunction, in her union with the gentle and half-oblivious Aubie, and in the seeming hopelessness of their wandering life with a stolen child. Still, nothing has been foreclosed. Dotty’s coiled and contradictory energies may transform her, or Aubie’s passive goodness may turn active.

The wanderers, however, meet and shelter with a decrepit rural family in which evil and hopelessness contend. Jiggy Huller is murderous and uncontrollable, a tenuously chained wolf. Alma, his wife, is his fat and slovenly victim; their two little daughters reproduce the pattern. One drowns their Barbie dolls, the other weeps.

Morris uses food, as much as anything, to suggest the outcast status of the Hullers in their backwoods, broken-down house. Alma spreads grape jelly on sugar cookies, or makes a breakfast of pretzels and beer. Aubie, who helps with the housekeeping, cooks Spam and macaroni, or cuts up hot dogs in tomato sauce. Meanwhile, Dotty is having sex with Jiggy and working on a scheme to demand ransom from Canny’s well-to-do family and return her after her five year’s absence.

The plotting goes on in an increasingly fetid and violent atmosphere. Jiggy takes up with his wife’s younger sister, and beats Dotty savagely. Jiggy’s degenerate brother assaults Canny. Aubie suffers, only half-understanding what is going on, but knowing that Canny will be taken away, and suspecting that Dotty may abandon him. It seems increasingly likely, on the other hand, that Dotty, despite her illusion of running things, will become Jiggy’s victim, as will Canny and Aubie.

The tensions build up to an explosion of violence. Dotty, pushed too far, can turn dangerous, as she did five years earlier with her degenerate father. Because part of the book’s strength is its suspense, it would not be right to reveal the ending, other than to say that it is grotesque and gory and that, in a sense, nobody really survives.

Morris is a powerful and promising writer. She handles her dismal story with delicacy and wit. These are not enough, finally, to provide more than momentum towards a doomed conclusion. “Vanished” sinks into its chamber of horrors.

It is Aubie who was to provide something else. He is meant not to survive the horrors but to transform them. He engages our compassion and, once in a while--near the end, when everything falls apart, he wonders if perhaps he is already dead--our imagination. But he is too pale and insubstantial. A victim does not suffice to redeem evil, or a story of evil, unless he or she is a saint as well. But sainthood requires work, or in any case, fire.