Few who saw the premiere of 20/20 on June 6, 1978 would have guessed that ABC's first attempt at the TV news magazine format would last 10 weeks, let alone 10 years.

Yet here it is, set to celebrate its 10th anniversary tonight at 8 p.m. on Ch. 4 with a two-hour retrospective filled with highlights from a show that has emerged from the considerable shadow of CBS's "60 Minutes" and established a considerable reputation for honesty and, yes, quality.There weren't many hints of impending credibility on that first "20/20" effort 10 years ago. Episode One introduced America to hosts Harold Hayes ( magazine editor) and Robert Hughes (an Australian art critic, of all things), two TV newcomers who were so uniformly panned they were axed before the cameras rolled on Episode Two. And the show's original format - a strange mix of investigative reports, humorous features and shallow gimmicks - prompted more than a few critics to liken it to the National Enquirer, and to chide then-producer Bob Shanks for proving that a "20/20" view of the world didn't necessarily mean clear vision.

The hour-long prime time news program did have a couple of things working in its favor, however. It was on then-top-rated ABC, a network hungry for a prestige program after climbing to the top of the ratings heap on the strength of popular mindlessness like "Three's Company," "Laverne and Shirley" and "Charlie's Angels." And it followed in the tradition of "60 Minutes," a much-respected ratings winner despite a slow start of its own.

So ABC went to work trying to fix the program. First it brought in proven TV veteran Hugh Downs to host the second installment. Then it tightened up the show's style, emphasizing investigative reports and consumer advocacy from a cadre of reporters that eventually included the likes of Geraldo Rivera, Silvia Chase, Tom Jarriel and John Stossel.

By the end of the summer of 1978 the show had improved enough to prompt ABC to give it a monthly shot until a permanent position opened up on the network's Thursday night schedule - right after hit sitcoms "Barney Miller" and "Soap." The next summer Barbara Walters joined the team as Downs' co-host, and "20/20's" impressive turnaround was completed, and its future suddenly looked like it had long-term possibilities.

Make no mistake about it - "20/20" has never been the ratings success "60 Minutes" has become. And it probably never will be. Every spring the show's staff holds its collective breath until the fall schedule is announced, never absolutely sure until the last minute that the program will be on it. And every fall and winter "20/20" comes through with respectable, if not spectacular Nielsen numbers - even this year, when ABC moved the program from its comfortable Thursday night home to Friday nights.

"That dumb move to Friday wasn't so dumb, was it?" joked Downs, an outspoken opponent of the move last spring. "We've surprised many people - including ourselves."

Victor Neufeld, the show's current executive producer, says the reason the show was able to survive the move to Fridays after nine years on Thursdays is that "we're an appointment program."

"Our audience, who watched us on Thursday night, came with us to Friday night," he told reporters in Los Angeles earlier this year. "We don't have to rely on whoever is still watching after the show before us ends. In fact, a big part of our audience isn't even watching TV during the hour before we come on the air."

But what is it about "20/20" that fosters that kind of viewer loyalty?

"We work very hard at the concept of being close to our viewers," Neufeld said. "We do pieces that reflect what we think is of interest around the country. We are not into ourselves and do stories we think we want to do."

More important than that, however, is the way audiences respond to Downs and Walters.

"To develop a successful news magazine, the key is to have people who the audience likes and wants to be with for an hour," Neufeld said. "I just think that there's a great deal of affection for Barbara and Hugh out there."

And nobody has greater regard for the "20/20" co-hosts than the two media stars have for each other.

"Barbara is the best interviewer and the best procurer of interviews in the business - hands down," Downs said. "She's as aggressive as necessary to get the facts. Over the years that I've known her, I've never seen an interview done by her where there was hostility or abrasiveness.'

"Hugh is underestimated," Walters said. "He is the figure that holds the program together. He is respected. He is cared about. People believe him. But because he is quieter, you somehow tend not to give him the credit that I think he deserves."

The same could probably be said of "20/20" itself. It isn't flashy and it doesn't often make headlines. But it's been there every week for 10 years, giving its small but loyal audience insights and information. I think it deserves a little 10th anniversary salute for that.

Heck, it probably deserves a salute just for surviving Episode One.