It was just a few years later - May 6, 1977. David Frost time. America watched, enthralled, as Richard Nixon, a former president of the United States, informed his British host that he had, indeed, made a mistake as chief executive: He had held on to his old employes, H.R. Haldeman and John Ehrlichman, too long. Richard Nixon attributed this example of extreme tardiness to his own helpful and compassionate nature: I wasn't a good butcher."

As it happened, one member of the enthralled viewing audience was a Certain H.R. Haldeman. He listened carefully as his old boss described the tearful firing of John Ehrlichman

"I said, 'You know, John, when I went to bed last night . . . I hoped, I almost prayed I would't wake up this morning . . . '"

Well, H.R. Haldeman, as he listened to those words, might have been a bit more touched by that particular reminiscence if it weren't for one thing: It so happened that those were the precise words Richard Nixon had used with H.R. Haldeman when he showed him the door. In fact, Haldeman - even though the disagreed with the firing itself - had always regarded those sorrowful words that accompanied the bad news as an especially moving memory he would always cherish.

That, at least, is what Haldeman's ghostwriter says. And the ghostwriter happened to be with Haldeman a few days later when John Ehrlichman called his (Tudor-style) Los Angeles home collect from prison. As old co-workers will, the two men discussed their former boss, Richard Nixon had irritated Haldeman even more by referring to him as "a splendid man."

"He must think we're dense," Haldeman told Ehrlichman. And then he went on to ask his painful question: Did they both get the same good-bye from the president?

Yes, said Ehrlichman; yes, the words were the same

And thus was a new and (from all early accounts) rather sensational Watergate book born: "The Ends of Power." You want to know how sensational it is? It's so sensational no one yet knows exactly what's in it. The security around that book is so fierce that the cynics among us may fear that much of its breathy appeal lies in the shimmering veil that shrouds it.

On the other hand . . . On the other hand, the flackery pushing the book claims that Nixon's No. 1 man, Mean, Tough, Stonewalling Bob Haldeman, is at long last feeding us yummies in his "bombshell memoir"

There's a moral in this somewhere.

And it may lie in what Haldeman's ghostwriter, Joe DiMona has to say:

"Haldeman felt that he alone had a very, very special relationship with Nixon," DiMona says deliberately. "He felt he was different from Ehrlichman, different from Kissinger and the rest.

"So when Nixon made that poetic speech about praying - that was a very emotional thing for Haldeman. I believe that bothered him more than even the 'butcher' statement." The Bombshell

It bothered him so much, in fact; that H.R. Haldeman, who had previously wanted to write a totally favorable, pro-Nixon book, suddenly changed his mind. Or, as DiMona says with a deliciously tantalizing smile, "The book will show that he believes Nixon is a great president. But that he believes Nixon is guilty of many things in Watergate and they should be told."

It bothered Haldeman so terribly, that he decided to tell the world just who erased those 18 minutes of tape; who he thinks Deep Throat is (former deputy counsel Fred Fielding, it is alleged by gossip columnists, but Fielding denies this), how he feels about wiretapping (he sees nothing wrong with it if national security is involved); and how he feels about his own participating in Watergate (he's sorry about some things; but, as DiMona says, contrition isn't exactly his favorite subject).

And finally, Richard Nixon's words to David Frost and America bothered Haldeman so dreadfully that he wrote a 40-page letter of disagreement to his old boss, listing his objections to various aspects of the show.

"Don't send it," advised DiMona, who is no one's fool. "Save that emotion for the book."

And gradually, Haldeman even revised his attitude toward DiMona, who, as an East Coast writer, represented so much of what Haldeman had always disliked. Joe DiMona is a very genial man of uncertain age ("Around 50," is all he'll says, and he smiles sheepishly as he says it); and he has a varied background. He's a lawyer who doesn't practice; he once wrote scripts for public relations movies; he wrote a book on court-materials; and he has a great deal of political savvy that he inserts in the novels he writes. Which is why Times Books chose him to work with Haldeman, and also - ultimately - why Haldeman came to like and trust him.

To be sure, it took eight months for Bob Haldeman to let down his ever-lengthening hair. It took the publication of DiMona's "The Benedict Arnold Connection," a novel about nuclear terrorism. Haldeman likes to take his family to all those disaster movies.

But once Haldeman had read that novel, which he found politically valid, he opened up more than ever. And Joe DiMona, who had at first been in the unhappy position of playing ghost to a defensive and reserved raconteur, changed his attitude toward Haldeman. May be you will be surprised at how DiMona (who covered the Mitchell-Stans trial for New York magazine) feels towards the Watergate criminal:

"Knowing his integrity as I do," DiMona says, "and no one knows a man's integrity more than this ghost, he would always insist on putting in material, even when it didn't make him look good . . . I'd trust him with every cent I have . . . " The Chilling Frost

In fact, the entire demeanor of Bob Haldeman can perhaps be divided into two categories: Pre-Frost and Post-Frost.

Pre-Frost, Haldeman was a mite frosty toward DiMona.

"I know you salivate whenever anything anti-Nixon, is said," Haldeman told his ghost one chilly night in January.

"He hated to be a part of the anti-Nixon press hysteria," explains DiMona. "He hated to give them any more ammunition.

"And then - " Di Mona beams hugely - "And then - Enter David Frost. This is beautiful . . . "

Well, you know what they say about the eye of the beholder. Suddenly DiMona beheld a beautiful talking Haldeman. Together they beheld their 50-50 share in a $140,000 book contract balloon into an estimated $500,000 apiece - maybe more. West Germany alone paid $250,000 for newspaper syndication rights.

Even Richard Nixon beheld the possibilities of such a memoir and phoned Haldeman to discuss their beautiful books. Yes, Nixon (like fellow Nixon alumnae Chuck Colson, Dwight Chapin and Ehrlichman) still calls Bob Haldeman, who is now in Lompoc prison and assigned as a meter inspector at a sewage plant. But Haldeman reports that his conversations with his old boss are rather stilted.

Post-Frost Haldeman demonstrated a decided courtliness as well as a sense of humor, according to DiMona's wife Barbara. "Right before he was about to be sentenced by Judge Sirica, we all flew back East from California," she reports. "And Joe and Haldeman were flying first-class, because The Times was paying their way. But I flew tourist.

"And Haldeman felt very bad that I was flying tourist."

So you know what he did? He sent a first-class chocolate mousse accompanied by a menu all the way to Barbara DiMona in tourist.And scrawled on that first-class menu were the words, 'Eat your heart out.'"

But Haldeman, being Haldeman, still did some of those old meticulous Haldeman-y things. Pre-Frost, when told who would be his ghostwriter, Haldeman checked out every single book by Joe DiMona from his local L.A. library. Which means that he must have read "Last Man at Arlington," in which the heroine remembers the Kennedy years very fondly and then goes on to say, "With Nixon as president, it makes you sick to say you are an American."

(DiMona suspects, not irrationally, that this may have accounted for some of Haldeman's initial coolness toward him.)

Post-Frost, Haldeman went into his den and showed DiMona "a whole raft of stuff he'd never shown anyone before. Nixon had consulted with him after Haldeman lefe the White House, but before his own resignation. And then there were notes of his meetings with Nixon at San Clemente."

DiMona smiles delightedly. "The minute his phone rings, that yellow pad comes out. And Haldeman said he's been so intent on being defensive for years, that he'd actually FORGOTTEN he had all these notes."

Post-Frost, DiMona found that Haldeman was still the boss, still very much in charge. "You don't write anything FOR Haldeman," he says, grinning. "He changed my book right down to the end. He rewrote, revised, edited for five drafts. He's very meticulous."

A chuckle. "You know in the beginning, I used to tell him, 'Always put in the details so people will know you've been there.' And he'd make a desperate effort to do that.

"But he used to tease me. He'd say, 'I know what YOU want in this scene: The hunched man behind the desk grunted - meaning Nixon, of course. Or, he waved his arms maniacally.'" Role Playing

DiMona was very sympathetic to what Haldeman was going through in the months they worked together - right up to the time Haldeman went to jail.

He understood the ambivalence the man must have felt about his old boss.

"I played the anti-Nixon role," he explains, "thereby trying to get him out of his defensive posture . . . I appreciated that he was going through a very, very tortuous situation. You see - some people, like John Dean, can adapt. But Haldeman is a very, very straight person and ultra-ultra loyal. Now he was in a position to see that Nixon was going to rewrite history to suit himself.

"So Haldeman was in favor of telling everything he knew, good and bad, about Nixon. Nevertheless I could tell this was a very emotional time for him. So even though we got into a few arguments (about what was going into the book), I knew it was agony for him - not for me. So why should I feel crushed?"

DiMona is very insistent about this. The Haldeman we perceived in the Watergate days is not the Haldeman perceived by his ghost. "That's what I'm trying to get across to you. That Haldeman is not a robot type.

"He had to be the Dr. No of the administration. He always had to be the bearer of bad news.

"He is reserved man and he's serious, but the chilliness he has to this day comes as a result of his experience with Nixon where he was under intense stress.

"you know Larry Higby, who worked with him at the White House as well as at J. Walter Thompson, says that when Haldeman was in advertising he was very easygoing. Not a robot.

"But he felt that was the way to do his job with this president. And because he did his job with that intensity and because of Watergate, the press has this image of him as being a robot type." Pressing Issues

However the press should feel toward Haldeman, it's clear that Haldeman hasn't thoroughly revised his feelings toward the press. It's understandale, says DiMona; after all, a reporter wanted to interview him at the airport before his appeal to Sirica (which prompted Haldeman to snap, "Don't you have any sense of decency?")

But one thing is certain. Just because The New York Times is paying Haldeman a bundle for his memories these days doesn't mean that Haldeman is overwhelmed with gratitude toward his new benefactors.

"I'll give you a colorful story," DiMona says with a grin. "I visited Haldeman about four times in prison and sometimes Tom Lipscomb (president of Times Books) came with me. Now Haldeman used to have to carry the manuscript from the visiting place to the sewage plant where he worked.

"So Lipscomb brought out a beautiful New York Times book bag for Haldeman - with THE NEW YORK TIMES printed on the outside. Which Haldeman accepts without comment."

The grin broadens with admiration. "Well, the next day Haldeman shows up with the book bag inside out."

Yes, in some ways he hasn't changed a bit. The money Haldeman earns from his book will probably all go to his lawyers. His future is still uncertain (DiMona believes a foundatin of some sort has approached him; for lecturing engagements, but isn't positive). Freedom

Toward the end of his freedom, Haldeman received a call from John Ehrlichman who told him about prison conditions: the food, the recreation - everything. It was an act of courtesy that moved Joe DiMona - these tow men, once so formidable in their power, once so powerful in their formidableness, now reduced to discussions of prison life.

Toward the end of his freedom, it was still all stiff-upper-lip and little outward display of emotion for Haldeman. It must run in the family. Haldeman's wife, says DiMona, is just the same.

"I never saw him rihgt up until the end, too. Unitl the day he went off to to prison. He never looked sad. Never gave any indication of bitterness."

How do you feel? asked DiMona.

And Haldeman replied, "I don't react to injustice."