One bright winter morning eight years ago this very week, Ronald Reagan was awakened by an aide.

"Sir!" said the aide urgently upon finding Reagan asleep later than expected. "In an hour and a half you're going to be sworn in as the 40th President of the United States!"The president-to-be, never one to leave a straight line dangling, rolled over in bed and pulled his pillow over his head dramatically. Then he wailed: "Do I have to?"

Yes he did. And millions of Americans are glad that he did, since Reagan has weathered the storms and stemmed the tide of opinion well enough through two controversy-filled terms to become one of the most popular presidents in recent history.

But not with everyone.

"I don't think history will prove him to be a good president," says former Speaker of the House Tip O'Neill in "Frontline's season-opening documentary, "The Real Life of Ronald Reagan" (8 p.m., Ch. 7). "He is the least-informed president I have known, with the worst grasp of the issues. Quite frankly, I don't think he leaves much of a legacy."

Or does he? "The Real Life of Ronald Reagan" attempts to provide more information on the subject so viewers can draw their own conclusions. By using film clips, interviews and an extensive collection of biographical data on the actor-turned-politician, "Frontline" producer David Fanning hopes the 90-minute special will help Americans answer a question that is on many minds as the Reagan Era gives way to the Bush Administration.

Who was that man? The film, produced by Martin Smith and hosted by noted historian Garry Wills, carefully documents the history: Reagan's early life in Dixon, Ill., where he dreamed of being "some kind of American hero"; his professional evolution, from radio baseball announcer to B-movie actor to president of the Screen Actors Guild to television host to political spokesperson to politician; and his presidential administration.

And all along the way are the thoughts and opinions of those who knew Ronald Reagan and worked closely with him.

"I thought it was a joke - running a motion picture actor," says former California Gov. Pat Brown, who lost his gubernatorial seat to Reagan in the 1960s. "But my attacking him as an actor was absolutely fruitless."

And as it turned out, Brown continues, "he was a better speech-maker than a governor."

"He is the best political candidate I have ever known," says longtime aide Lyn Nofziger. "Not that he's the smartest . . . but that he understands the role of being a candidate, that somebody else is running the mechanics of the campaign. He's the kind of man who's willing to listen and accept an idea even if it isn't his."

Bill Plante, the CBS News reporter who covered the White House throughout the Reagan years, says he learned very quickly that this man would be a different president.

"While I was following him around on the campaign trail I heard him say some very odd, very contradictory things," Plante said during a PBS press conference here earlier this month. "So I compiled a lot of information and on April 4, 1980 I ran what I thought was a devastating expose on his inability with facts. I thought it would kill his candidacy, but the story was met with massive public indifference.

"That pattern continued with several other stories until I finally figured out that the public didn't much care. They liked what he stood for, and so they didn't much care if every T was crossed and every I dotted."

Former Reagan aide Michael Deaver told reporters that he felt that fate helped make the president invulnerable to media attacks. When Reagan survived an assassin's bullet three months into his first term, "the Mr. Nice Guy of all those Reagan movies was fused into reality because reality was acting like the movies. And thereafter, in my view, he was a larger-than-life figure."

And the media never understood that, said Wills.

"I think the values and the America that Reagan spoke for went right over the head of a lot of the press," Wills said. "And the reason that the media's criticism of him had no effect is that there was a disconnect between the public and the people speaking to the public.

"Reagan was representing certain values, good and bad, that the Eastern establishment press was not used to taking seriously," Wills continued. "That's why they didn't take Reagan seriously enough."

But they're taking him seriously now even though in two days he'll just be one of four living ex-president's (and the only one of the four who likes to refer to himself as "an ex-actor"). "The Real Life of Ronald Reagan" is probably just the first of many similar journalistic attempts to break through the Reagan mystique in an attempt to figure out how the president's popularity could survive Iran-Contra, an ever-increasing national debt, administrative scandals and continued claims like the one from O'Neill that Reagan "lacks the intellectual energy to make decisions."

And, like this one, all of those forthcoming specials will probably conclude that Reagan's success had little to do with the invasion of Grenada, his ability to use television and radio or even his improved relations with Soviet leadership. Rather, the essence of Reagan was probably best summed up on the program by his former chief of staff Howard Baker.

"I believe Ronald Reagan is the most presidential man I've ever known," Baker said, "and that will be his principal legacy."