MALCOLM Stevenson Forbes loves to do a lot of things at once. Even when he's just on a tethered demonstration ride in his favorite balloon, he'll: josh with the photographers clustered around the basket, converse by remote control with a TV show, reassure his passenger, wave at friends in the crowd and manipulate the gas jets with casual skill, all the while checking gauges and keeping an eye on the halyards and straining fabric of the huge balloon, the very devil to control because it is in the rectangular shape of a French cha teau. His cha teau.

He grins, and his eyes sparkle behind the horn-rimmed glasses. Because he is the center, the core, the focus of every envious eye, the marvelous machine making everything go. The ringmaster. Hell, he's the whole circus: acrobat, wirewalker, juggler, roustabout, and he's having the time of his life. Such a wonderful time that you can't help forgiving him his boyish chutzpah and maybe even his millions.

Of course, on an ordinary day at the Manhattan office of Forbes magazine, he doesn't have quite so much fun. But he tries. HIS secretary comes in at 8:30, summoned by the jewel-encrusted jade Faberge' buzzer on his cluttered desk. Methodically, he attacks the two-inch pile of papers: A memo on some circulation figures. A note to Harley-Davidson Motorcycles. A letter to the 1941 class agent at Princeton. "Thank you so much for the great compliment of that invitation . . . unfortunately, prior commitments . . ." A note to a pal, ending in two exclamation points. In separate piles before him, papers with clippings attached, fodder for editorials. Suddenly in midquote he looks up, asks, "Have I used an exclamation point in this letter yet? . . ." BY 9:28 the secretary will leave and another will spell her. An hour later a third will take over. Forbes has been here since 7. It is just another Monday. He has a lunch date at noon with the Duchess of Gloucester aboard his $2 million, 126-foot yacht, and this afternoon he will drop by a couple galleries to buy a painting and check out a major exhibit to which he has loaned part of his Faberge' collection. He owns 10 jeweled Faberge' eggs, as many as the Kremlin has. They are reputed to be worth well over $10 million.

They say Malcolm Forbes' public image is his greatest creation. Owner, editor-in-chief and sole stockholder of the booming Forbes magazine, which nets an estimated $10 million a year with a circulation over 700,000, he has become a sort of folk hero for the would-be-rich because he acts out the fantasies of the millionaire they dream of being.

There is the ballooning: the pioneering flight across America, the aerial adventures in Pakistan and China, where he cut the tether against the orders of government officials on the scene and took off, landing on an army base. There was the motorcycling tour of the Soviet Union. There is the 47-room cha teau in France, the historic Battersea House mansion in London, the Fiji island, the 400-square-mile tract in Colorado, the Wyoming cabin, the Montana ranch, the fishing camp in Tahiti, the Far Hills estate in New Jersey, the Manhattan town house, the Moorish palace in Tangier.

And the collection of 80,000 toy soldiers (complete with museum and full-time curator staff), and the 300 antique toy boats, and the Americana collection including letters by George Washington, Abraham Lincoln and William Henry Harrison (who held office only a month and whose autograph cost Forbes a record $132,000), the original Mason-Dixon Line plan ($396,000), Lincoln's opera glasses, the Enola Gay log of the Hiroshima flight and Paul Revere's expense account for his ride.

There are a lot of millionaires around. In fact Forbes magazine has published a celebrated report on the 400 richest Americans--for which Malcolm Forbes, though listed, declined to reveal his worth. (It is said he nets $25 million a year and has a fortune upwards of $200 million, and that figure depends on how you handle the Colorado tract, which he bought for $3 million in 1969 and later sold a third of for $50 million . . .)

"I owe it all to hard work, initiative . . . and the death of my father," he is fond of telling people, flashing his famous conspiratorial smile. The smile has been called "wicked," "wolfish" and "gleeful," which may be true, but more than anything it is enormously engaging.

There is another, unsmiling side, as is only natural. He can be demanding, dictatorial, overbearing with the help. He expects to get his way, and usually does.

In any case, he does seem to enjoy life as no millionaire has since the vintage days of Newport, Tuxedo Park and Palm Beach. He's got that balloon shaped like his 17th century Mansard-built Cha teau de Balleroy. Any evening he might fly to Morocco for an extravaganza in his palace with feasting and belly dancers. He wears a satin bowling jacket with "Capitalist Tools" on the back, and he gives his friends tins of "Capitalist Tool" cookies. Once he gave the mayor of Moscow a "Capitalist Tool" tote bag souvenir. The motto is even inscribed on the corporate DC-9. And then there's his office.

All right, how would you decorate your office if you were making $25 million a year? His has two fireplaces, oak paneled walls 40 feet long and 15 feet wide covered with: a Gauguin, a Renoir, a Homer, a Bellows, a Gainsborough, a Reynolds behind the desk, a giant Rubens at the far end.

There are four pictures of himself--not counting the big oil of him in the lobby looking like an astronaut in his cycling outfit--and other snapshots in a flotilla of family portraits set on tables. Plus two ship models, a crystal balloon sculpture celebrating the Forbes Magazine Balloon Ascension Division, a wall full of university degrees with the academic hoods draped over them (he collects these, too--has 18 so far), a gift revolver, an ashtray that says "The best man for the job is often a woman," and on the mantel among the assorted medals "the First Annual Fran Lebowitz Fun Capitalist Award."THE pace picks up: the hectic schedule letter; the prior commitments letter. "I'll be in Europe on those days and Bertie will be on the ranch in Wyoming . . ." Christopher (Kip), the third son, drops by to discuss gifts for the duchess: a Battersea House plate and Capitalist Tool cookies. "How about the kerchief?" Fine. All this time the outer office is fielding calls. "Yes, you could write him a letter . . ." An aide comes in to get instructions about ordering a cigar humidor, buying a new rug for the stairs, fixing a turquoise ring for Mrs. Forbes. "What about the red shirts I ordered?" They haven't come in yet. "Why not? It's been a week." Mumble and shrug. "Well, I'll rely on you to follow that up." And the car, something has to be done to the car . . . WE check out the seven-story plant, currently being expanded for the 300-plus employes. Forbes is especially proud of the new gym, which employes are encouraged to attend three times a week for a variety of fitness classes.

"Me? I exercise as little as possible," he says. Weekend motorcycling keeps him trim at 63, though he eats well, loves good whiskey and wine. The wine cellars in his townhouse, next door to the magazine at 60 5th Ave., run to 12,000 bottles, according to "Malcolm Forbes, Peripatetic Millionaire," a useful and evenhanded biography by Arthur Jones.

He takes the front seat of the green Mercedes, driven by Kip Cleland, the lithe Forbes Inc. physical fitness director and "guardian" who goes almost everywhere the boss goes. Forbes never travels alone. The second son, Robert, who has given up his shoulder-length hair and full beard, comes along, but it is really Kip's party. Kip met the duchess through the Victorian Society in which he is active.

The oldest son, Malcolm Jr. (Steve), can't make it today. He will inherit control of the magazine, of which he is president now, and Kip, now involved with advertising and promotion as associate publisher, will become publisher. Robert manages the firm's real estate. The youngest son, Tim, a documentary filmmaker, and the still younger daughter, Moira, who with her husband Kenneth B. Mumma runs three Philadelphia suburban weeklies, are not as closely involved with the family enterprises.

Mrs. Forbes is not here either. She spends as much of her time as possible at the Montana ranch. The former Roberta (Bertie) Laidlaw, she frankly hates publicity and parties and the general uproar that follows her husband everywhere.

Down at the dock on West 23rd Street, we are piped aboard the "Highlander" by a bagpiper. When the children were young, they had to learn the bagpipes and stand, kilted, in a row by the gangplank to pipe guests onto the yacht. They finally rebelled in 1970.

There are 45 people at the party, including Walter Annenberg's sister, the president of Guinness-Harp, the chairman of H.J. Heinz, the British consul, some bankers and the top people of the Britain Salutes New York festival. The duchess, accompanied by a lady-in-waiting and a stone-eyed guard, turns out to be young, blond, Danish and stunning. As we start in on the beluga caviar and Ritz crackers, the yacht pulls out of its berth for a tour around lower Manhattan.

Lunch: roast duck with mandarin orange, beef with horseradish sauce, corn souffle', spinach souffle', carrots with pecans, noodles Romanoff, wild rice, stuffed filet of sole, saute'ed and marinated mushrooms and fish aspic, with a fine '71 Margaux and a California '80 fume' blanc. Dessert is billiard-ball-sized California strawberries and homemade cookies, slightly, somehow endearingly, overdone.

Forbes, who regularly holds business parties on the yacht, moves among the guests with practiced ease, now stopping for a confidential buzz with one of the men, now chatting expansively with the women. The noise level rises quickly. A happy party. The duchess gives him a photo of herself and her husband, signed Birgitta and Richard. The man who bought the Social Register beams with delight.

On landing, he sees everyone off to their limos. But a freelance photographer is left over. Dressed in work jacket and jeans, she had drawn disdainful looks from the yacht officers, but Forbes unhesitatingly had invited her to join the lunch. Now he spots her looking lost and wondering how she is going to find a cab in this urban wilderness of docks and vacant lots.

Forbes stops the car, gets out, brings her to the staff people standing about and directs them to take care of her.HE hands the secretary still another clipping, a magazine ad showing a crystal goblet. "Buy me one of these, would you? For a sample. I might get them." Next problem: He wants to see a play in which a staffer has a part, but an art auction is in conflict. Also, the same day he speaks at the Greenbrier Hotel deep in Virginia. "When's her big moment? The second act?" Yes. Maybe he can arrive late? Or if he can get to the auction early without a fuss? "Would you check that out and let me know." A note about a new restaurant for his slambang "Non-critic's Critique" column. Then, rapidly: a name for the Christmas card list; a medical form; a bill; a clipping about Kip for the company bulletin board; an order for more jelly beans, "minimum chocolate and licorice . . ."'MY father never lost his burr, you know. His father, Bertie Charles Forbes, who founded the magazine in 1917, was born in 1880 in Aberdeenshire, Scotland. I vowed I'd never work for him because I thought we'd never get along. Then after the war when I was making $90 a month, I was thrilled to get a job at $100 a week for him. I got married a few months later and he raised me to $110 in a burst of Scottish largess. I must say money went further then, but not that much further."

B.C. Forbes, one of 10 children of a country storekeeper, taught himself shorthand, became a printer's devil and then a reporter at $2.50 a week in Dundee, where he went to college at night. He came to New York in 1904, eventually became the highest-paid syndicated columnist of his day, writing on finance for Hearst. Malcolm was the third of his five sons. Ten years after B.C.'s death, and upon the death of the eldest son Bruce, Malcolm took over sole control of the then-struggling magazine.

"I had written my senior thesis at Princeton on weekly newspapers," he says. "I was burning with political ambition and thought if I built a chain of weeklies in a state like Ohio, with its blend of agriculture and industry, it would give me a strong political base. Of course I soon discovered that I just didn't have time for my weekly column. I was breaking up pages, sweeping up newsprint, running around to sell ads and then collecting for 'em on Thursday so I could pay the help on Friday."

That career ended with World War II. Staff Sgt. Forbes came home with a leg wound, a Purple Heart and a Bronze Star. (It wasn't the last close call: He has survived a coup d'e'tat shootout in Morocco that killed 100, a motorcycle crackup and several balloon crashes.) The political career came later: New Jersey state senator 1952-58, Republican candidate for governor in '57, delegate-at-large to the Republican convention in '60.

"The big money didn't really begin till the '50s when the magazine got its footing. By the mid-'60s we were really rolling. With no stockholders, it worked. If we couldn't do it out of cash flow, we wouldn't do it: Never get big enough so you'd have to go public. But it was my father's financial column that kept the magazine alive in the Depression. We kids had the advantage of good schools and all that, but it was not exactly living licentiously. We'd take the train to work like anybody else, the ferry, the subway. I worked six days a week. When the five-day week came in I thought it was the greatest thing that ever happened." A charming, self-mocking smile suddenly ignites. "I was a true socialist!"

In 1971 he put the magazine on a four-day week but abandoned it after a year because the exceptionally lean staff couldn't maintain continuity adequately.

In the world of financial magazines, Forbes magazine today is right up there with Fortune and Business Week. The biweekly gets mixed grades. On the one hand it is seen as lively, readable, tough, aimed at the individual investor. Many read it just for the zesty flavor of the chief's epigrammatic Fact and Comment column. On the other hand, it is also seen as superficial, quirky, "the People magazine of the business press."

"It thrives because it offers something other than the basic business reader's needs," commented Robert Lubar, a veteran Fortune editor. "It's entertaining in its rather flippant way. Fortune is more serious, deeper. I think Forbes has moved a lot in our direction in the last couple of years. It's more thorough, with longer articles, and the layout's not so pedestrian."

Forbes himself admits that in the early days "we fell between two stools: Business Week did the news better and Fortune did the in-depth corporate story better."

Forbes editor James W. Michaels, one executive said, is "the marketing genius who made it what it is, and Malcolm's great wisdom was to get out of the way." Rivals charge Forbes with running favorable stories to get ad contracts, and they resent the tax-deductible arrangements by which family and company ownerships, from ranches to mansions, yachts to planes, are interwoven.

"As a family-owned private firm they can play a lot of games the public corporations can't play," an editor said, somewhat wistfully.

The emphasis on people, Malcolm Forbes says, is the magazine's great strength. "My father used to say he'd never buy stock in a company based only on its balance sheet. He said he'd have to be impressed by the man at the steering wheel. An annual report is basically history, and it's basically deceptive in that the story is not in the figures but in the footnotes."

The Forbes focus, he adds, is on people in the sense of trying to appraise a management as to capability and character.

"Two to four times a week we have chief executive officers to lunch with key editors, Steve and myself, and we entertain them in the 'Highlander' with their wives. We get 25 or 30 for every home football game at West Point, sail at 9 a.m., breakfast, lunch and dinner, and at the end of the day you know them, you get a feel for it which you don't get in a give-and-take across a desk where they know they're being interviewed and are on guard. People think of these initials, IBM, GE, GM, as monoliths, but they're nothing more than a handful of people with responsibility at the top who are making the decisions . . . It's who has the wheel who determines direction." Tomorrow is the Philly day, when his son-in-law is getting a law degree at Villanova. The shoulder of the thin blue blazer will have to be repaired. "Call Mrs. Forbes and ask her to leave it in the kitchen so it can be picked up." Magazines to read on the trip: the business and newsweeklies plus the impolite British "Private Eye": He reads voraciously. Everything. Constantly. Next, a Harley-Davidson convention at York, Pa. A degree presentation in Ohio. "I'll duck the dinner. You find yourself saying the same things you're going to say the next day." A letter to Pakistani officials, thanks, and can they make the balloon weekend at Balleroy? Four newly bought paintings, Western landscapes, stacked against the wall, have to be taken to the Wyoming ranch. "I'll be at Wyoming in July, not the Colorado ranch." An aide reports on the packing for Colorado. "Why will it take a week? You got a truck lined up?" A black tie dinner tonight. "Remind me I'll need some money . . ."WE stop at the posh Joanna Dean Galleries on Fifth Avenue while the chauffeur parks illegally outside. Forbes owns a large painting by Radovan Trnavac-Mica, a male nude on loan for a show here, but after a quick look at the artist's new work, he decides he doesn't want any more. However, when he is shown an even larger superrealist painting by William L. Haney, Forbes is interested. It's full of energy, a scene of someone getting emergency heart treatment on the sidewalk at Times Square. "Critical Response Time," it's called.

"What's the lowest price he'll take?"

Forty-five hundred, Forbes is told.

"I'll take it."

That's that. We're back in the car and headed for the Faberge' show at A La Vielle Russie, an even posher gallery, where owner Peter Schaffer escorts us around past lines of oohing, aahing viewers. Later Forbes returns to the office for more dictation and possibly a nap.

In 1965 he went to a Parke Bernet sale, caught auction fever when a gold-and-diamond Faberge' egg came up, estimated at $12,000. He paid $45,000 for it. "I went home that night and couldn't sleep, I was so undone by it all," he says, "but then I met the underbidder, Alexander Schaffer, Peter's father, and he opened his safe and showed me all his treasures, which really set me on the trail."

This is probably Forbes' most valuable collection, the one that excites him most because he feels Faberge' created a whole new art form with diamond chips and flakes.

"At the beginning I only bought things I liked, but as you get into it you figure you need examples of this genre and that, you round out the collection, buy things you wouldn't just get for yourself. It evolves."

The autograph collection is thrilling too, since each letter is unique in a way a Picasso or a Renoir isn't. "I never set out to have a collection. The soldiers? Oh, that's just nostalgia that got out of hand. I tell my wife, 'Look at the prices they bring now.' I don't tell her I was the one who drove them up. My father would be absolutely aghast at all this. Spending your sinews on something you don't really need. But he'd understand the enormous appreciation."

He and his sons Steve and Bob are still acquiring Faberge's, buying up to 20 new pieces a year. Their value has simply exploded over the last 20 years. Kip has written a book on the subject, and Tim has made a documentary film about it. In fact, the whole family is into collecting, both for themselves and for the magazine.

"I had a Monet waterlily, and Kip told me it wasn't a very good one and that if I'd sell it, he'd invest the money in Victorian paintings. He'd been studying them since college."

In those days Victorian paintings were scorned and unfashionable. Now, partly because of Kip's purchases and writings, they are chic. Kip has 150. He also collects Napoleon III items and Mission furniture. Bob, a former staff photographer for the magazine, specializes in antique photographs, and Tim used to collect old movies until he got into films for himself.

Malcolm Forbes enjoys his children. "They're our best friends," he likes to say, "and they're each other's best friends. When they went away to school we stopped treating them like they were our responsibility. It's very hard for parents to grow up, I think. It's easier for kids to grow up than for parents to mature in terms of their kids, and not feel they have to advise and admonish, point out their faults and everything. Let your children go."

His own childhood was harder than theirs. "We five brothers were pretty rivalrous, not as close as my children are. We had to learn a new hymn every Sunday. My father would sit there playing poker with his friends and we had to recite a hymn before we could go out to play. We got 10 cents for it."

It has been pointed out that his collections feature things in miniature: the toy soldiers and boats, the dioramas of Western towns that he commissions, the Faberge's, the epigrams that he has published as "The Sayings of Chairman Malcolm": "FAILURE IS SUCCESS if we learn from it." "A MATURE PERSON one who agrees with you." "THE UNDRIVEN don't get there," and so on. Even the balloons, by this argument, lift him up to a height from which the world looks puny and the people like ants.

But then, when you live with large numbers, as most of us do these days, whether it's fortunes or budgets or population figures or megatons or bytes, maybe it's useful to reduce things to a comprehensible scale, just as a presidential letter reduces the dimensions of history. "History isn't chiseled in stone, it's what some guy did at the time," he says.

That's the thing about Malcolm Forbes: Whatever you may think of him, and his money, and his publicity, and his balloons and motorcycles and gems and wisecracks and castles and junkets and his sheer, unabashed, baldfaced joy in living his life, he's human scale all the way.