BOOK REVIEW : A Backwoods Valhalla Hosts Battle Between Good, Evil : A GOOD BABY <i> by Leon Rooke</i> Alfred A. Knopf $18.95, 264 pages

Leon Rooke’s fable of primal good versus primal evil is set in the backwoods of the backwoods of the reeky, foggy mountains of Western North Carolina.

The struggle in “A Good Baby” is as stark and doom-ridden, in a way, as the wars in J.R.R. Tolkien’s “Lord of the Rings.” And despite its graphic horror, native madness and hormonal extremes, it manages to be about as oddly cheerful.

Rooke’s hero, Toker, an innocently high-sexed venturer, has more than a touch of Hillbilly Hobbit. Truman, the baleful villain with a brain rotted out by hatred and religious mania, is a creature out of Mordor.

Each has an astonishing, hyper-Appalachian eloquence of speech and rumination. The author imparts it in language so twisted and down-home funky that it can disappear in a cloud of skunk-hollow baroquery, shortly to emerge and conscript us, barefoot and spitting, into the hollow’s mists, myths and comic monstrosities.

“A Good Baby” begins with the world undone by an act of gratuitous evil. Two quests follow, one of light and one of darkness. At the end, the light prevailing, the world is healed. Renewal, via a passionate sexual encounter and the good baby of the title, is under way.

So much for the classical form. As to the particulars: Truman, unshaven, stinking with hate, one cheek swollen with a rotting tooth, takes a young woman he has made pregnant up into the mountains and slits her throat. Somehow, the baby manages to get born. Rooke is not strong on obstetrics, nor, for that matter, on pediatrics: The newborn baby is immediately doing all kinds of things only a 2- or 3-month-old could manage.

Toker finds the infant, scoops her into a bag and tramps the hills searching for a woman to take care of her. He encounters a variety of candidates, some willing and some not; all picturesque. In fact, it is not long before he becomes so attached to his bag-baby--whom he feeds various oddities, including tobacco juice, and washes by creek-dipping her--that he inclines to keep her.

Meanwhile, Truman also is prowling the mountains--in a decrepit black automobile. He is a self-appointed preacher who sets up in competition with God as a kind of Satanic figure calling himself the Caretaker. He is after the baby; she will be his Familiar.

Toker’s search for a foster mother leads him to stumble across the corpse of the real one. He is joined by allies: the victim’s dwarf sister, whose own search has been aided by a ghostly spirit on horseback; an ancient stalwart with second sight named Hindmarsh, and Bathroby.

Bathroby--she wears a green bathrobe, mostly--is the new Eve to Toker’s new Adam. She is Daisy Mae sexy and Katharine Hepburn feisty. She and Toker have a series of spitfire encounters culminating in a bed-busting union, and the promise of restored life with bag-baby. First, though, the four children of light--Toker, Bathroby, Hindmarsh and the sister--bury the dead woman and, in a water duel, destroy the Evil one.

Rooke has written a story in which everything is done, told and thought in an exuberant white heat. He has created a backwoods Valhalla in which everyone is a god, demigod or devil, with larger-than-life passions and idiosyncrasies. His achievement is to have managed, largely, to make larger-than-life live. Almost without exception, the denizens of Cal’s General Store--the center of the backwoods community--are strange enough to be mythic, and real enough that when they leave the room, we miss them.

This is hard to do; to succeed with the three central figures is harder. Bathroby is the least successful and the closest to a lusty stereotype; yet her energy and comic outrageousness work to set off Toker’s inquiring susceptibility and quietly heroic determination.

Toker is open, elusive and not completely defined. This is a virtue. Goodness is a mystery; otherwise, it is good behavior. Still, we see a lot in Toker: He is awkward, scrupulous and kind; he has a touch of iron, and he is pulled by an unstoppable impulse towards the light. Both he and Bathroby have traveled a long way out of very dark country: Her father went mad and hanged his young son; his mother went mad and burned her daughter to death.

Truman’s urge is back to darkness. He is pure evil--and scary; yet he is also inept and, in a strangely distorted way, even innocent. Hatred is his ecstasy--Rooke gives us, rather tritely, his recollection of a girl who tormented him as a child--and he raves apocalyptically.

“I have commingled with moth and cockroach, no less than winged pterosaur,” he hears his God telling him. “I have burrowed Thue rankest slime to invent earliest mollusk stewin in my brain.” And when limping along on his quest--he has managed to blow up his car: “So here he was, his tail dragging. A man had no dignity on foot anyhow, and he hated that. On foot a man was akin to muskrat and hedgehog, to glairy beast in sorry quagmire.”

Even as ravings, such language can overdo itself. Rooke is hardly ever lean, and his mannerisms sometimes clog up. In a few pages, we read of “licey” mice, “mossy” cornstalks, “fungussy” rot, and of “pickish” blessings, “vixenish” women, “smilish” dogs and “hurtish” feet.

Yet for the most part, his verbal fireworks create this backwoods kingdom as a place both in and out of time. As readers, we have to assume an awkward and unfamiliar gait to enter it; once entered, we move about for the most part entranced.

Next: Elaine Kendall reviews “ Instead of You “ by Constance Schraft (Ticknor & Fields).