WHO KNOWS WHAT EVIL lurks in the hearts of men? Thomas Berger knows. And like the Shadow, Berger transforms the terrible news into dark and haunting laughter.

In his 12 novels, Berger has exploited (and exploded) the Western novel (Little Big Man), the whodunit (Who Is Teddy Villanova?) and the Arthurian romance (Arthur Rex). But in books like Sneaky People, Neighbors and The Feud, he returns to the bland anonymity of small- town America, a past and present never-never land of shady lanes, white frame houses and little boys playing ball.

Not that he finds anything soothing in these familiar scenes. Only Nathanael West has come close to Berger's vision of terror, chaos and depravity under the surface of "normal" American life. Look with Berger's eyes, for example, at that boy playing ball. Suppose, let's say, the lad let it roll into the street. In the universe of The Feud, a police car skids to a halt, and Harvey Yelton, lecherous chief of the Hornbeck Police, jumps out to warn:

"You oughtn't play ball so it comes into the street. You know why? It could hit somebody's automobile and scare them so they would lose control of the wheel and drive up over the curb and turn over and burst into flames, and everybody in the car would be burned to a crisp, see? . . . Or you and your friends might tear after the ball onto the road and you'd all be killed if a big Mack truck was coming along real fast, or you'd scare the truckdriver and he'd smash into them high-tension wires, which would fall down and electrocute the whole neighborhood and kill everybody and burn up all your houses, maybe get outa control and burn everything in the whole town, see."

Something very much like that is what happens in The Feud: On an ordinary October day, Dolf Beeler, "a good husband and a nice man," goes from his home in Hornbeck into the neighboring town of Millville to buy paint remover. Dolf makes a false step while choosing between a pint and a quart, and suddenly finds himself staring into a pistol wielded by a man he had thought to be a Protestant clergyman. "You went to buy paint remover and you had a gun pulled on you?" Dolf thinks in amazement. But pistols aren't the worst of it; before long, the misunderstanding over turpentine has plunged the Beelers of Hornbeck and Bullards of Millville into a fiery landscape of shotguns, carbombs, arson, attempted robbery, mental collapse, coronary thrombosis, suicide, sodomy, resisting arrest and assault with custard pies.

The two sides in this battle are not hillbillies in wool hats, but solid citizens of an idealized 1930s landscape that looks a lot like rural Pennsylvania. They are not fighting about money, sex, land or even princple; in fact, nobody is quite sure what the whole thing is about. But it's war nonetheless. "We got our pride at stake here," explains Reverton Kirby, a stalwart of the Bullard faction. "They get away with that, and the next thing you know they'll be riding us down like dogs and violating our women and all."

As in other wars, there are tender moments. Bernice Beeler, recently fired from her job as a theater usherette, is shopping uncritically for a father for her unborn child. And Tony Beeler, Dolf's dutiful but confused 17-year-old son, finds himself playing Romeo to Eva Bullard, Bud Bullard's precocious daughter. Eva lets Tony fondle her "milk fund" at a local dance; he flees when he discovers she is almost 13, then decides to marry her and join the Mounties. This plan collapses when Eva eats both French crullers from Tony's bag of mixed doughnuts, and they part forever. But first, like star-crossed lovers in all wars, they try to make sense of the conflict around them. "It's probably a comedy of errors," Tony says. "Well," Eva answers, "I don't know if it's anything to laugh about!"

Fortunately, Berger knows it is. I marked my copy of The Feud with a star wherever its blend of irony, parody and slapstick made me laugh out loud; some pages look like a map of the Milky Way. My favorite moment comes when Bernice, having seduced Harvey Yelton, confronts him with the news that she is pregnant: "I don't have to remind you of what you'n'me did the other day," she says.

Somewhat surprised, Yelton replies, "That was just yesterday. . . . Everybody in the world but you, I guess, would know you can't get pregnant one day after inter- what-do-they-call-it. Now, anybody but me might get real mad about that . . . And if he was carrying a gun, he might shoot you with it."

In presenting this pageant of ignorance, rage and deceit, Berger is harsh but never cruel. In all their variety, his novels have consistently presented a serious view of humanity as a race utterly spoiled by something that looks a lot like Original Sin. This merciless vision frees Berger somehow to love even his least prepossessing creations.

Certainly one would need to read widely to find a figure less prepossessing than Reverton Kirby, a skinny runt with a pistol in his waistband and a chip on his shoulder, eternally on the prowl against the faceless enemies he imagines creeping up behind him. Reverton has "a gift for blaming the wrong people for his difficulties" and the habit of opening phone conversations with such gambits as "You goddam dirty yella dogs! I'll git you and all your tribe! You'll eat dirt afore I'm through with you, and you'll like it!"

In the Beelers, Kirby finds what he has long wanted-- a tribe of enemies who are numerous, confused and unarmed. Somehow, by the book's close, he has found his own brand of heroism and peace--and the reader has seen him as a soul capable of loving and inspiring love. Berger is all the more powerful assa novelist because he can make us care about Reverton without dropping his detached, ironic pose.

"Why, down in the coal country," Reverton tells his cousin Bud, "they got mines that been burning real quiet since the Year One. All of a sudden smoke and fire shoots out of the cracks in the ground, and boils the water in the ponds, and the ladies do their wash there."

Something much like that happens in The Feud: Thomas Berger taps into the fire down below, and turns it into something cleansing and safe. That he makes it look easy only adds to the achievement.