He showed highlights from the past: two men in tuxedos exchanging wedding vows on the air, footage of an abortion performed at a Chicago clinic, Jane Fonda calling Richard Nixon a war criminal.

He trotted out to field a few last questions from the audience.

Finally, his staff popped the corks on a few dozen bottles of champagne and doused him with the contents until his pin-striped suit and trademark white hair were soaked.

After almost 29 years and nearly 7,000 shows, after 20 Emmy Awards, after interviews with presidents, generals, cross-dressers, crusaders, adulterers and Nobel laureates, Phil Donahue videotaped his last show today.

The man who virtually invented the single-topic talk show -- and made it so powerful and profitable a force in daytime TV that a swarm of imitators muscled in and eventually drove him from the airwaves -- has put down his mike. The presidential candidates will have to make do with Larry King. The caller, as Donahue always referred to a questioner on the phone, will have to dial Ricki Lake instead.

"We never thought we'd last 29 days," Donahue told a raft of reporters after the studio audience had filed out and the cameras were turned off. Someone asked if he thought he'd launched a revolution. "We've had some sea changes in our culture, and we were able to offer a platform where people could talk about them," Donahue replied. "If that's a revolution, okay, we're happy to be part of it."

He'll be much in the news for a day or two. And the shows he's completed, plus reruns, will be shown on affiliates around the country (including Channel 9 in Washington) into the summer. But after today, "I have no professional commitments," he says. It's the first time that's been true since Donahue, 60, was a student broadcaster at Notre Dame in the '50s.

He'd hoped for a discreet farewell. "It's not fun talking about your death, y'know," he said earlier in the week, relaxing in his office in jeans and a plaid shirt and round glasses. In fact, Donahue had said very little in the months since his decision to end his long run was announced in January.

But in his last week, as media interest intensified, he was willing to burnish his history a bit, take a few final potshots at his critics, muse about the future. "Donahue" and its offspring have changed the culture and changed with the culture. Its host was not about to give William Bennett, who excoriated talk shows last fall as "an indicator of social decline," the last word. The Phones Were on Fire'

It may be difficult, in a decade when new talk shows pop up like mushrooms after rain, to grasp how radical an approach the original "Phil Donahue Show" represented. It was 1967 in Dayton, Ohio. A popular variety show had been canceled and Donahue, a local radio interviewer, was given its morning time slot. "No band, no couch, no desk, no announcer, and a studio audience" inherited from the canceled show, Donahue remembers.

No stars, either: Dayton was too far from anywhere to attract celebrities. "We had to do what was left to us -- issues," Donahue says. "It wasn't any prescient gift on our part. We were faced with a daily professional reality: Phyllis Diller isn't available, so you'd better come up with issues people care about."

From the beginning, Donahue's formula combined newsmakers and provocateurs -- his first guest was atheist Madalyn Murray O'Hair, followed a few days later by a leader of the Mattachine Society (dedicated to equality for homosexuals) -- with shows about family, relationships, consumerism (Ralph Nader was Donahue's single most frequent guest). One early show discussed the pros and cons of birth control pills. "Women were able to call and talk about water retention and breakthrough bleeding!" Donahue remembers, with great enthusiasm. "The phones were on fire."

Perhaps that was his greatest innovation -- bringing the audience, both in the studio and at home, into the process. Donahue first allowed his audience to question guests during commercial breaks, then realized that what resulted was dramatic, unpredictable -- good television, in short -- and began hustling along the aisles with his hand-held microphone.

Those audiences were, of course, largely female, and it's probably not coincidental that "Donahue" and the women's movement advanced together. "It showed a view of the world in which women mattered," says Gloria Steinem, who appeared on the show -- the staff counted -- 17 times. "Any social justice movement is really based on people telling their real-life stories and on other people realizing they're not alone, that it's not an individual problem, it's a political problem." Donahue brought ideas and issues from domestic violence to sexual harassment to a national audience, she points out.

Through the '70s, when his face adorned magazine covers and his memoir became a bestseller, and into the '80s, Donahue had no real competitors. But everyone who's wielding a mike in a studio now was watching then.

His descendants acknowledge their indebtedness. "There isn't anyone on television with a talk show who isn't doing Phil Donahue," Sally Jessy Raphael said this week. "I owe it to him that I wear out high heels running around the audience." And Geraldo Rivera called him "the role model for the best of what we do." But so many people began doing it that the pioneer began to lose ground.

Dethroned as the country's most-watched talkmeister in 1986 by neophyte Oprah Winfrey, who's been the reigning Nielsen queen ever since, Donahue held his own in the ratings for several years. The competition kept increasing, however: Geraldo went into syndication in 1987, Regis and Kathy Lee in 1988, Maury and Jenny and Montel in 1991, followed by Jerry, Ricki, et al. Fourteen talk shows currently vie for an audience that once belonged to Donahue and Raphael alone, an audience that's further tempted by dozens of cable channels and armed with zappers.

By last year Donahue, who'd once drawn 30 percent of the viewers in the markets where he aired (Nielsen calls this a 30 share), had fallen to a 14 share. More problematically, his audience had aged along with his show; he drew comparatively few of the 18- to 49-year-olds that advertisers lust for. "I look at these other shows and all the guests have their baseball caps on backwards," Donahue says, for once sounding like a 60-year-old.

When "Donahue" was dropped last year by WNBC, its flagship New York station, "the handwriting was on the wall for all concerned," says Janeen Bjork of Seltel, a "rep firm" that advises local stations. "You lose New York City and you know it's your last season." In February, the most recent Nielsen ratings book showed "Donahue" tied for eighth place among daytime talk shows, behind a cluster of his sometimes unruly, but now more successful, progeny. Nonsense Now and Then'

Donahue has always been of two minds, or maybe three or four, about the shenanigans he and other talk hosts have had to resort to for ratings. This is a man who interrogated Watergate figures, was the first Western broadcaster to visit post-meltdown Chernobyl, landed Nelson Mandela's only talk show appearance after his release from prison. He also wore a skirt and heels three times for shows about cross-dressing; the highest-rated "Donahue" of 1991 was a transvestite shopping spree.

A confessed political junkie, he could conduct a compelling conversation with a 16-year-old boy and his 44-year-old girlfriend, "but he'd really rather interview Bob Dole," says former producer Ed Glavin, now co-executive producer of "Jenny Jones." Glavin and other staffers would "sit in our offices watching talk shows. Phil would sit in his office watching C-SPAN. If you walked in during a House vote, it was like interrupting the fourth quarter of a bowl game."

Glavin recalls once telling his boss that the very last day of the May "sweeps" ratings period was upon them. Donahue fell to his knees in his office and dramatically sobbed "Thank you, thank you" in not-entirely-mock gratitude.

Yet for years he's waged a spirited defense of talk show tactics, his own and others', and questioned the purity of network and print reporters who've raised the sleaze issue -- while making it plain that he wasn't so thrilled with some of that stuff himself. "I'll get through life if I never preside over another male stripper show," he says sardonically. And then adds, "But I'm proud of them. Women were hysterical. One guy set fire to his jockstrap -- I'll never forget it! A little nonsense now and then is treasured by the best of men." Besides, he notes, "they kept us alive." And Donahue was always clear about not wanting to sacrifice his show on the altar of tastefulness.

On the whole he thinks the genre has done more good than ill, helping to forge a more open, less shamed society. "The personal testimonials you hear on TV are from people who've saved themselves -- from addictions, from abuse, from being closeted," he says. "Betty Ford did that on the Donahue show. Kitty Dukakis came on. Are there some who are self-indulgent? Maybe so. But our critics are so focused on narcissism that they fail to see the number of people who've been enlightened by these programs."

Whereas the host meets such people all the time. They come up to him in public and thank him for the help or information that enabled them to leave abusive marriages or tell their parents that they're gay. "There is a salutary effect to what our critics call psychobabble," he concludes.

Critics figure prominently in his reminiscences. They've been there from the first, expressing shock and horror -- Atheists! Homosexuals! -- and they're unmollified decades later. The most recent were virtues chronicler William Bennett and Sen. Joseph Lieberman (D-Conn.), who held a press conference to blast the televised "rot" that "degrades human personality." Part of Donahue's reluctance to scold or judge other talkfests stems from his desire to not give aid or comfort to their common enemies.

"Ease up, monsignor," is his response. "I'm very Republican in my view about daytime television: I say, let the marketplace work. The last thing we want is a bunch of wealthy white men . . . tripping over their robes, saying Ain't it awful?' And being cheered on by the conservative Christian Coalition, who want to tell your neighbor what to watch."

Talk shows "can be outlets for the disenfranchised," he still believes. "Along the way, we'll see some excesses -- phony guests, overambitious producers who manipulate audiences or plant questions. . . . But if you do that often enough, it will be apparent to the viewer and those shows will fall of their own weight." And Now . . .

Starting Friday, Donahue is suddenly at leisure. He's financially secure, "a lovely place to be, a feeling my father never had," but not ready to truly retire. He says he doesn't know what he's going to do next. Meanwhile, "Everyone's looking at me like I'm some kind of science project."

He's already taped two specials for NewsTalk Television, a 24-hour cable channel he owns a chunk of, but hasn't committed to more. He's had desultory discussions with radio networks. "I think they're looking for a left-wing Rush Limbaugh. I have, with gratitude and respect, passed."

There's always politics, though he's not encouraged to see the likes of Bill Bradley and Pat Schroeder leaving the arena he's considered entering. "Could I find happiness going to a large apartment on Park Avenue and asking for money as a pro-gun control, anti-death penalty, pro-gay rights, pro-choice, pro-affirmative action citizen?" Donahue wonders, sounding dubious but not willing to close off the option completely. "It certainly doesn't sound attractive. Then I feel guilty having said that -- hell, if I don't, who will?"

So for now, "I've got a boat." It's a "42-foot, twin-screw trawler-type vessel" berthed near his Connecticut home, and its skipper likes to cruise at about 10 knots. He also likes to circumnavigate Manhattan, with a soundtrack on an onboard stereo. "I take you to the Statue of Liberty and I play Kate Smith," he says. "We go to Ellis Island and Ray Charles sings America the Beautiful.' Then I turn around and show you the skyline and you hear Frank Sinatra singing New York, New York.' And by that time, you're calling me Sir.' "

But how many hours can you spend running a private Circle Line tour? To borrow a talk show theme: Is Donahue's wife, actress Marlo Thomas, worried about living with one of those Retired Husbands Who Just Loaf Around the House All the Time? "I dunno," says Donahue with an amiable shrug. "I think she is, to tell you the truth." CAPTION: Champagne all around: The granddaddy of the television talk show gets doused after taping his last program yesterday in New York. CAPTION: From top: The first show in Dayton, Ohio, in 1967, with atheist Madalyn Murray O'Hair; one of several times Donahue wore a skirt for a show about cross-dressing; and Hillary Rodham Clinton autographs a copy of her book.(Photo ran in an earlier edition) CAPTION: Talk show host Phil Donahue, hugging his wife Marlo Thomas and pointing to a friend in the audience yesterday, after taping his last "Donahue." CAPTION: One of several times Donahue wore a skirt for a show about cross-dressing.