(FORTUNE Magazine) – IN SHARP contrast to Donald Trump and Silvio Berlusconi are billionaires you probably have never heard of, men who work hard -- and successfully -- at being invisible. Take Donald W. Reynolds, who started almost three-quarters of a century ago selling newspapers on the streets of Oklahoma City. Today his Donrey Media Group in Fort Smith, Arkansas, owns 57 dailies in 20 states. Yet he is virtually unknown outside his company, and even within Donrey only a few key employees see much of him. He lives in a fortress-like home near Las Vegas, jetting into Fort Smith in his private Boeing 727. Why do some billionaires try to hide? Shyness is one reason. Class is another. ''It's more tasteful,'' says one. A third motive is to avoid hassles. As Michael Phillips wrote in his book, The Seven Laws of Money, wealth can bring lots of headaches. Envy. Endless pleas for donations. Kidnapping. Terrorism. Finally, a few just might have something to hide. Secrecy does not come cheap. For those willing to pay, a coterie of professional minions-cum-martial-arts-experts stand ready to scramble phones (at least $600), debug offices ($1,500 and up), and scope out restaurants ahead of time, as well as thwart the advance of fans by stepping on their feet ($55 an hour). The ultimate, of course, is a private island. The Bahamas, with 700 shards of palm-treed sand, offers a wide selection, from $300,000 (ten acres) to $4 million (500 acres). But the solitude isn't complete. Says Rodney Dillard of Sotheby's International Realty: ''A lot of people think if they buy an island, they will get sovereignty. But it can't be done.'' Sovereignty doesn't buy much in the way of safety anyway. With the aid of a battalion of Gurkhas, the Sultan of Brunei, the richest man in the world, has managed to keep his tiny, oil-rich country quiet since a brief rebellion in 1962. King Hassan II of Morocco, who is said to have baraka, or soldier's luck, has survived three assassination attempts. In an abortive coup in 1972, Moroccan Royal Air Force fighters riddled his 727 as he returned from France. The quick-witted Hassan grabbed the plane's microphone and, pretending to be a crew member, radioed that the king had been ''mortally wounded.'' The attackers thoughtfully stopped firing to avoid harming other passengers. The plane landed on one engine, and Hassan escaped into the nearby woods. Islands and kingdoms aside, Switzerland is the haven of choice. It has more known billionaires per capita than any major country -- approximately one in 360,000 -- and about half were born elsewhere. Though the country no longer holds a monopoly on secrecy -- Austrian and Hungarian banks, for instance, offer greater confidentiality -- it still boasts the best overall package. Residents of Switzerland are not allowed to disclose ownership in companies, and for the very rich income taxes are negotiable. If that's not enough, the Swiss Bankers' Association publishes a 100-page guide to ''asset management'' that includes a list of 22 tax havens around the world, including little-known Nauru in the South Pacific. The pamphlet describes intricate maneuvers that in many countries would look a lot like tax evasion. One industrialist who takes advantage of all Switzerland has to offer is Otto Beisheim, owner of Metro International, a retail and wholesale giant with $25 billion in annual sales. This West German entrepreneur, who introduced the concept of ''cash and carry'' to Europe -- a process in which a retailer pays cash to the wholesaler and takes the merchandise with him -- is not known by sight or by name in the Swiss town of Baar, where he lives. His unpretentiousness is nothing new. Old-timers at Metro recall that the day before Beisheim opened his first cash-and-carry market in 1967, he was painting lines in the parking lot. His wife was inside erecting a jewelry booth. For a native Swiss, circumspection comes as naturally as yodeling. The Andre family, owners of Andre & Cie, a $6.8-billion-a-year international trading company in Prilly, live so quietly and conduct their affairs so discreetly that even their closest advisers don't know how much they are worth. Their holdings include Garnac Grain, a Kansas-based company that controls nearly 10% of the world's grain market, plus shipping companies, cattle ranches, and coffee-processing plants. For generations, the Andres have been part of the Plymouth Brethren, a religious group that seeks to restore the simple, austere life of the early Christians. Not for them lavish chalets, priceless art collections, or soirees with the Bianca Jagger crowd. The Andre clan -- Henri, Eric, and Pierre -- lead modest, middle-class lives near Lausanne. Equally inconspicuous is their countryman Mark Diethelm, a quiet, serious fellow resembling an overweight bank clerk, who owns Diethelm & Co., a $1.5- billion-a-year diversified trading company. With the exception of an interview last year in the Swiss financial magazine Bilanz, Diethelm has steered clear of the press. Don't look for his picture: a worldwide photo search came up empty. Playing confidential banker to this club is an equally secretive Lebanese- born financier who glides quietly about in a limousine bearing the license plate EJS 555. EJS stands for Edmond J. Safra. The number five, many Middle Easterners believe, brings good luck. It seems to have worked for Safra. Since his early days in Lebanon, where he helped his father finance camel caravans, Safra has built a worldwide network of banks from Tokyo to Buenos Aires to New York, where he controls Republic National Bank. Along the way he acquired a celebrated clientele of wealthy Latin Americans and Arabs by providing personal investment advice through the private banking arm of his empire, the Trade Development Bank. Safra sold his bank to American Express in 1983 for $550 million, and went along as chairman. He departed 18 months later for reasons that were never fully explained. In 1988, on the expiration day of his agreement not to compete with American Express for five years, he opened a new private bank in Geneva. Safra Republic Holdings is on the same street as American Express. Perhaps afraid that Safra would take back some of his old customers, a few American Express representatives earlier this year apparently did some whispering that tied Safra to drug-money laundering. Safra threatened to sue. In August, American Express revealed that as a settlement it had paid $4 million to some of Safra's favorite charities. A few days later the company said that it had actually settled for $8 million. Why the discrepancy? As with so many matters involving Safra and his money, questions remain. Until recently one country appeared even more secretive than Switzerland: the Soviet Union. In the absence of a Russian billionaire, we offer an American who operates like one -- Whitney MacMillan, powerful chairman of Minnesota-based Cargill, the largest private corporation in the country. If his name doesn't ring any bells, don't feel dull. Despite running a company that handles about 25% of world grain trade and employs more than 50,000 people, MacMillan remains eerily anonymous -- even in agricultural and commodity-trading circles. Cargill's worldwide intelligence network controls the flow of information in and out of the company with the sophistication of the KGB. Marvels Ralph Nader, who conducted countless interviews with friends and relatives of MacMillan for his book The Big Boys: ''There were businessmen in Minneapolis who had never heard of him.'' The private persona of Whitney MacMillan -- a tall, handsome man with a full head of silver hair -- comes as hermetically sealed as the business one. Conversations with some of his closest pals, including George Pillsbury, who is married to MacMillan's cousin, and Yale classmate G. Richard Slade, president of the Minneapolis College of Art and Design, present a picture of a quiet, competitive man who is as formidable on the tennis court as he is in business, but who remains aloof from his own community. Besides his family -- pals say wife Elizabeth is his best friend -- his one outside passion seems to be international politics, particularly issues involving the Soviet Union, which he visits often. MacMillan has been criticized privately by his fellow CEOs for not giving more time and money to cultural and charitable organizations -- Cargill reportedly donates less than 1% of pretax income. He did, however, take the time to travel to Moscow last June with the Minneapolis Children's Theatre. His older brother, Cargill MacMillan Jr., is just as private. Last year Cargill divorced his wife of 30 years and married an executive secretary named Donna who worked at the company. As is the way along the shores of Lake Minnetonka, where the clan lives, the incident was kept so quiet that a year later a local gossip columnist had still not heard of it. Friends are not forthcoming. ''That's a whole other story,'' says Pillsbury cryptically. ''The blind is going down.'' And so ends our peek into the lives of the world's unseen billionaires. The MacMillan brothers remain an enigma, as do all the others. And that is for the best. Because, maddening as mystery is, reality might be worse. Do you want to know what dashing, dealing media mogul Rupert Murdoch really talks about at lunch? Taking up jogging, and the new diet book he just read. Sound familiar? Like maybe too familiar? Fantasy is a lot more fun.