"Wife Swap" may already be a hit, and its tawdry title couldn't have hurt. An episode of the new ABC series was "sneak previewed" Sunday night and ranked No. 1 during the hour it aired with those precious 18-to-34-year-olds. Ratings for the official premiere -- tonight at 10 on Channel 7 -- will give a better indication of the show's earning potential.

But never mind that business stuff. What "Wife Swap" does earn is your interest, and quickly, and not because it's anywhere near as sleazy as the title would make it sound. It's a reality show, yes, but also in its way a fascinating pop sociological experiment, one that increases in complexity and impact as it goes along. "Swap" has something for the most securely planted couch potato and the casual viewer as well.

In the first place, the sexual aspects of wifeliness are barely mentioned and certainly not portrayed. Two women from dramatically different environments trade places for two weeks with cameras recording just about everything they and their adopted families do. On tonight's premiere, a sinfully wealthy dunce from New York City changes places with a hardworking, down-to-earth mom from suburban New Jersey, and both are in for illuminating shocks.

Jodi, the Manhattan multimillionaire, has four nannies looking after her three children, whom she rarely sees, plus a maid and a driver. A (too-talky) narrator tells us that "the most important thing to Jodi is 'Me Time,' " and does she ever have oodles of it. Jodi likes to shop, get pedicures and chitchat cattily with her vain and vacuous friends. She dines out regularly with her hubby and, at home, rarely dirties a dish -- which is fortunate because she probably doesn't know how to wash one.

Her counterpart, Lynn, married to a blue-collar hombre from New Jersey, gets up at 5:30 to cut wood for a family business, drives a school bus and cooks and cleans for her husband and two daughters. Jodi barely makes it through the wood-cutting, giving up after 15 minutes, which is about as long as Lynn can stand Jodi's rigorous shopping agenda. A $2,000 shopping spree leaves Lynn cold; she already misses her real home. "Money can't buy what I have," she says.

Meanwhile Lynn's husband, Brad, is finding Jodi hard to fathom, harder to tolerate. "You have done nothing, nothing," he shouts at her during their first fight. He says that comparing the wimpish Jodi with the flinty Lynn is just about pointless: "It isn't even a question of different worlds. It's different planets." When Jodi recruits Brad to replace her at wood-chopping and some of the housework, he laments, "This useless woman has found a way to become even more useless."

The rules for the experiment require that for the first week, the women merely tumble into their new living environments and splash around. Then in the second week, they take over, making whatever feasible changes they can. The show is so well-produced (by Fiona Kenneth) that we are given just a smattering of background on the two families and then plunged into the proposition but feel we know plenty to understand the predicaments and ironies. A shot of the New Jersey family sitting on the sofa and watching TV evokes that similar and now iconic image from "The Simpsons," but one can sense the presence of love and respect in this house too.

Obviously the fate of the series will be tied to the colorfulness of the couples who are selected for the experiment and agree to participate. Based on this initial encounter, "Wife Swap" is promisingly sly and serious, funny and flabbergasting. And if the Simpsons happen to be watching, they'll probably get an idea for a great episode of their own.

'Kevin Hill'

The new TV season now upon us might be called the "What-the-hell?" season. Several of the pilots are implausible to the point of preposterousness, but you can almost hear network executives saying, "Sure it's unbelievable and absurd -- but what the hell, it just might work." The suspicion lingers that these birds don't really know any more about the public taste than my fat Aunt Fanny.

(In the interest of preserving the sanctity of journalism, I wish to state I do not in fact have a fat Aunt Fanny. I made her up. In fact, I made up most of the "new fall shows" I've reviewed so far this season. No, no -- I made that up. But honest, nothing else in this preview was made up by me.)

"Kevin Hill," one of the best-looking shows ever to emerge from the hardscrabble UPN network, may indeed have one of the most outlandish premises of the year. It's so contrived that it could just as well be a parody on Fox's "The Mad Show." And yet as tonight's premiere -- at 9 on Channel 20 -- makes clear, believability may be an overrated virtue, especially in this era of reality shows that contain all kinds of fakery, phoniness and petty fraud.

Taye Diggs has the title role in "Kevin Hill," playing a hotshot, incredibly well-tailored Manhattan lawyer whose job appears to be something like the one Tom Cruise had in "Jerry Maguire," the care and feeding of egomaniacal athletes. It doesn't matter, because he doesn't have the job for long. The key complication in Hill's life, the fact that his late cousin left him a 10-month-old baby girl named Sarah, gets him fired. He lands another job with a less prestigious and, until his arrival, all-female law firm.

It's not hard to believe that a fellow who looks like Diggs would have a busy social calendar and spend few nights alone with Spike TV. But the arrival of Sarah changes virtually everything about his life, and watching him deal with the frustrations, while also coping with his undeniable love for the gorgeous tot, is pure pleasure, if not sheer hilarity.

By coincidence no doubt, the first case he has to work on at the new law firm is one much like Kobe Bryant's -- a superstar athlete charged with sexual abuse. But this is not by any means the "Order" half of "Law & Order." It's a lighthearted but not unaffecting show about a little fish who doesn't even know she's out of water and the havoc she causes in her posh new pond. Agonizingly, Hill even has to turn down a weekend in Vegas with a screamingly gorgeous girlfriend (whom we see in her red bra and panties) because the baby needs him. "You know I'm a movie star, right?" the astonished girl asks on the phone. Yes, he knows, but his priorities have just been turned upside down.

And whether or not Ms. Red Underwear is a movie star, Taye Diggs is definitely a television star. If this vehicle doesn't carry him merrily to the top, then another one will.

Chop till she drops? Manhattan millionaire Jodi, left, struggles to fit in with a blue-collar New Jersey family.Lynn tries to fit in with her rich new family in ABC's "Wife Swap." Her counterpart, Jodi, has a tougher row to hoe.In "Kevin Hill," Taye Diggs plays a Manhattan lawyer who grows attached to Sarah after the 10-month-old girl is left to him.