The trouble began at the Grace & Truth Bible Conference in Rapid City, S.D., in 1932, when a man named Johnson, leader of a sect of fundamentalist Sanctified Brethren, sermonized against women's slacks.

What was abominable to God back in Moses' time deserved to be abominable in 1932, he said. And he got his ammunition from Deuteronomy, 22:5:

"The woman shall not wear that which pertaineth unto a man, neither shall a man put on a woman's garment for all that do so are abomination unto the Lord thy God."

Johnson's proclamation led to a split in the congregation and some listeners walked out. The walkees, the men modestly attired in long pants and the women in long dresses, were one of several "exclusive" branches of the sect (as opposed to the "so-called" Open Brethren) who later became known as the Cox Brethren. These actually were the Beale Brethren, also sometimes known as the Cold Water Brethren (before the falling out with the Johnson wing), a term deriving from a dispute with the Birds and their followers who preferred hot baths.

The schism between the Johnsons and the Beales, or Coxes (not to be confused with the Reformed Sanctified and the Dennis Brethren) probably continues to this day.

If you don't believe this, take it up with Garrison Keillor. His chronicle of the Sanctified Brethren and about 10,000 other American realities is found in obsessively exact, wholly true-to-life-detail in his latest book, "Lake Wobegon Days."

"Storytelling is a strange little business," offers Keillor, who is also the creator of the enormously popular radio program "A Prairie Home Companion," in his tentative way as he stares into the middle distance. "You learn early that when people admire you for doing it well, you start to lose the ability."

Novelists, he says, "create characters who stride across our landscape. But with radio it is more likely that we enter into theirs. In Lake Wobegon, it is a set of characters who live against the listeners' own backdrop. I speak their lines in my own voice, pretty flat, don't dramatize. The listeners will do that much better than I will . . . "

Here in the rolling farmland south of St. Paul where Keillor has spent much of the summer lolling about, some say the tale of the splits among the shaggy-bearded Sanctified Brethren of Lake Wobegon, Minn., is just a shaggy dog story.

"How far is Lake Wobegon from reality?" asks Keillor, his green eyes focusing somewhere beyond the window of his upstairs bedroom in the recently restored Victorian-era, Pratt-Taber Inn here. "You'd have to ask someone who lives out there. I never claimed to be all-inclusive or absolutely accurate."

But in fact, "Lake Wobegon Days," now topping the national best-seller lists, is an absolutely accurate account of Our American Life and Times. (Keillor will present portions of that account to Washington Tuesday night during a benefit reading -- already sold-out -- at Lisner Auditorium.) The only peculiarity is that the book business bureaucrats somehow have gotten things screwed up again. "Lake Wobegon Days" is being listed as a novel, as though it were fiction, something Keillor simply made up.

Hardly anyone who knows Keillor's work will accept that. They understand that few know more about the actual comings and goings of most of us than Keillor, whose initial step toward understanding the native American dream can be traced to the moment some years ago when he changed his first name from Gary because he wanted to be a successful writer.

Ever since 1974, when Keillor launched "A Prairie Home Companion" (heard in Washington on WETA-FM 90.9 from 6 to 8 on Saturday nights and repeated Sunday afternoons from 1 to 3), the most successful live variety show in radio broadcasting history since television, he has edged closer and closer to complete comprehension of the elusive realities governing all life within the borders of the world's mightiest democracy in the waning years of the 20th century.

"You start to know people when you start to take their lives in your hands and make crucial decisions for them," he modestly admitted during a languid interview on a sultry, languid recent afternoon.

As for himself, Keillor has always, or almost always, or at least for the past decade or so, seemed to know where he came from -- the town called Lake Wobegon. Increasingly, other Americans are coming to understand this. At last count, about 2 million Americans -- and more every week -- tune into their local American Public Radio station to pick up Keillor's variety show for the music, poetry and featured monologue that catches them up with the goings-on in Lake Wobegon. And the writing is on top of all this.

"I write an awful lot of stuff, man," he said as he contemplated the past few years. "I don't believe it! I just overflow with stuff. I thought it would diminish, but there's an incredible amount of stuff unfinished or half-finished. I don't do anything else, really."

He says he returned to the characters of Lake Wobegon for the book because "I thought I could put in the historical part that you could never do on radio. The parodies of 19th-century correspondence, the memorial prose . . . You couldn't do this in the frame of a radio narrative . . . it wouldn't sound right."

His tales of the Skoglunds, the Bunsens, the Krebsbachs, the Inquvists and other denizens of Lake Wobegon are "starved for detail in literary terms," he said. "You just can't supply that on the radio. The listener supplies it. You can sort of carry them along with your voice, but the listeners carry along the details, which to me makes this different from fiction."

The author of the Lake Wobegon chronicles, both written and spoken, is a genuine contradiction -- a man of palpable, painful shyness who is becoming rich and increasingly famous by singing, dancing, sermonizing and humoring his polished, homespun way into the hearts and minds of the nation's most pampered, parodied and preyed-upon consumers, the Yuppies.

Since the book is an autumn dual main selection of the Book of the Month Club, and his publisher, Viking, happily reports 450,000 hardcover copies in print, and Keillor's now busy flogging the book on TV talk shows, we have a right to know everything about him -- shyness be damned.

So for the record, Keillor is 6 feet 4, has dark hair cut long, wide-set green eyes in a squarish sort of face beneath beetling brows, a generous mouth, tobacco-stained teeth, a low but extremely resonant voice, and has one 16-year-old son from a long-gone marriage.

On this particular day, he is dressed in faded jeans, a neon pink sports shirt with tropical plants on it, red socks and sneakers. He has made a big thing of owning just one suit, a white one, which goes nicely with red socks.

Geographically speaking, Keillor can be said to spend most of his time in St. Paul, not very far from Anoka, Minn., a blue-collar suburb of the Twin Cities where he was born on Aug. 23, 1942, the third of six children.

In fact, he seems to reside in the community of his own creation, Lake Wobegon, in Mist County, Minn. This is a locality that seems at once not far from Winesburg, Ohio, or the place Thornton Wilder once wrote a play about, or any of a number of other mythic American towns where Life Itself actually resides.

Keillor has been honing his vision of this place for a long time. He sold his first short story to The New Yorker 15 years ago, and has appeared there more than 30 times since. He has sold four pieces to The Atlantic and two to The New York Times Magazine. An earlier book, "Happy To Be Here," a collection of many of these stories, sold well in the early 1980s. And although his popularity has soared, he is clearly uncertain how long it will continue -- or how long he will even let it.

Keillor said he thinks the radio show may last another three or four years, but not much longer than that. "I don't know. But based on how I feel now, I think I could do three more years. The question is not how long could you possibly do it . . . but it's a strategic decision . . .

"We all like to avoid pain and humiliation, that sweet, rotting odor of failure. You want to do it while you're still getting applause. Everybody has seen the guy who tells two, three jokes, he's got the audience in the palm of his hand . . . and it stinks.

"You start to pity him, you just want to beg him to get down from there. But failure makes him go on."

Comedy, for Keillor, must show compassion and concern for the world. "Comedy that doesn't care about the world doesn't interest me," he mused. "And there's a whole streak in comedy that is cruel, that picks on weaker people. But it's false comedy."

He has been re-reading some Twain. "He's still funny. Twain's after-dinner speeches still make you laugh out loud and it's a hundred years old. There just isn't anyone else from the 1880s who can do that to you."

Of contemporary humorists, Keillor likes Roy Blount Jr., and then turns quickly to the late S.J. Perlman and E.B. White, the comic stalwarts of The New Yorker's golden age.

Otherwise, he says, "I read a lot of good trash . . . like Jackie Collins. But the problem with her is the covers. I'm afraid to touch her book, the color will come off on my hands and then people for five more years will say, 'Oh, you read Jackie Collins.' "

As for his own book, Keillor says he thinks it is being read so widely because "the charts are kind of empty now. It's a good time for someone to move in with some stories friom Minnesota. But in a few weeks, it will be time for James Michener's Texas novel.

"The first week, it will occupy numbers 1 through 10 on the charts. It's going to sell 500,000 copies in Texas alone. My little tome gets a few weeks in the sun, then Texas rolls over us. It just doesn't seem fair, does it?"

Even so, Keillor seems certain to return to Lake Wobegon, whether or not Texas steamrollers him, whether or not the radio show lasts for many more years.

"I'll be curious about the people of Lake Wobegon longer than the radio audience will be," he says, and there is a glint in that glance to the middle distance.