By - Louis S. Richman

(FORTUNE Magazine) – Decades of breakneck building have transformed Southern California into a spaghetti maze of freeways that weave through a sun-drenched oasis of tract houses spilling across the boundaries of towns with Spanish names. But the region's sometimes heedless growth has still largely spared a duchy-size spread of 65,200 acres in the heart of Orange County. This palatinate, quaintly called the Irvine Ranch, has made Donald Bren, 55, the 92% owner of the company that controls the property, the newest member of America's real estate nobility. Squarely in the path of the southward push of Los Angeles sprawl, the Irvine Ranch is perhaps the choicest parcel of undeveloped land anywhere in the world. And Bren has a grand vision of remaking his dusty acres as the 21st- century Sunbelt equivalent of the Medicis' Florence -- with office parks instead of cathedrals, condos for palazzos. ''There's a California renaissance coming,'' he says. ''We want to produce a great urban culture that balances development and environmentalism to yield a quality of life unmatched anywhere.'' If he can pull it off and keep California's militant no-growth spoilsports at bay, Bren could end up the richest property owner in America. His penchant for big dreams, painstaking attention to detail, passion for quality, and boundless self-confidence are traits Bren shares with the other real estate billionaires on FORTUNE's list. In other respects, these moguls are a diverse lot. Office developer, hotel builder, and one of New York City's largest residential property owners, Harry Helmsley, 78, is a retiring Quaker but a punctilious dealmaker worth $1.3 billion. He finances his buildings as conservatively as he used to live before marrying his second wife, Leona, 67, a onetime model for Chesterfield cigarette ads who courts publicity as queen of Harry's 23 hotels. She and her husband won notoriety last year when Rupert Murdoch's New York Post printed allegations that they had falsified invoices to spend company money on a multimillion-dollar refurbishing of their estate in Greenwich, Connecticut. The Helmsleys denied any wrongdoing. Chicago's Jay and Robert Pritzker, worth $1.5 billion, run businesses that include Braniff Airlines and an industrial conglomerate in addition to their large share of the Hyatt hotel chain. Although the Pritzkers -- Jay is 65, Robert, 61 -- hide their wealth behind a wall of holding companies, they dress their hotels with showy opulence. Hyatt Regency Waikoloa, a $360-million Hawaiian pleasure palace set to open next year, will have a seven-acre lagoon stocked with flamingos and tropical fish. J. Willard Marriott Jr., 55, his mother, Alice, 79, and brother Richard, 48, are the largest stockholders of the 240-hotel Marriott chain and as such have accumulated a net worth of $1.3 billion. The Marriotts are devout Mormons who manage their caravansaries with the strict discipline of boot camp drill instructors. A. Alfred Taubman, 62, made his $2.5 billion as a builder of gas stations and shopping centers and owner of the A&W restaurant chain. Initially one of Bren's partners in the Irvine Ranch, he sold his stake after the two developers clashed. Since buying control of Sotheby's auction house and the Woodward & Lothrop and Wanamaker department stores, Taubman apparently has mellowed from a fiery-tempered autocrat into a civic-minded merchant prince and art patron. But Sam LeFrak, 69, an exuberant homebuilder and New York City's largest private residential landlord, worth $1 billion, has an earthy explanation for what drives Taubman and the rest of America's biggest property developers: ''It's the only business I know where you get to play God.'' Donald Bren is a complex, even mysterious, character. The perpetually tan and supercool California golden boy conceals a tightly wound, somewhat shy perfectionist. His friends call him ''tough,'' his detractors ''ruthless.'' Bren shows his extrovert side in a yen for beautiful women and fast ski trails. Twice divorced, he is the father of two sons, Cary, 28, and Steven, 27, and a daughter, Ashley, 19. Bren the introvert spends contemplative vacations studying European church architecture, or retreats to the mosquito- infested backwoods of British Columbia in search of trout. He is the product of an affluent Hollywood upbringing. His father, Milton, produced the hit Topper films of the 1930s; Milton and Donald's mother, Marion, separated when Donald was 11. Marion then wed Earle Jorgensen, a wealthy California businessman and confidant of President Reagan. Milton Bren, who became a real estate investor after World War II, married actress Claire Trevor. Says Donald Bren: ''In effect, I had four demanding parents insisting that I excel in whatever it was I did.'' Family connections and a $10,000 bank loan helped launch him into Southern California's booming housing market in the late 1950s. Beginning as a builder of custom homes, he graduated to planned residential communities. Stylish work set Bren above his competitors. He married his Mediterranean-style houses to such amenities as golf courses and shopping centers -- a commonplace notion now, but innovative at the time -- and planted expensive, mature trees to make the grounds handsome in a hurry. Good design and a robust market helped Bren sell homes, but it was timing and luck that made him rich. In 1969, a good year for Southern California real estate, he sold his development company to International Paper for $34 million in IP stock. He bought it back two years later, during a slump, for just $22 million. His profits helped him bag Irvine, whose vast acres were a developer's dream. Pieced together in the late 19th century by a San Francisco merchant of Scottish extraction named James Irvine, the ranch was being run by a conservative foundation that slowly sold off or developed the land, paying only small dividends to James Irvine's heirs. The foundation's stewardship infuriated Joan Irvine Smith, the founder's litigious great-granddaughter; she lobbied for a 1969 change in the federal tax code that forced the foundation to sell the ranch. Bren pounced. Too small to buy the property himself, he joined forces with Taubman and other partners, including Smith. In 1977, Bren ended up with a 34% stake in the business. In 1983, Bren borrowed $518 million to buy out all his major partners except Smith. He also offered to buy the shares controlled by Smith and her mother, but they are holding out for three times what Bren has been willing to pay. Since Bren gained control of the ranch, the southern California real estate market has rebounded. An acre of Irvine residential property that sold for $250,000 four years ago fetches nearly twice that today. But Bren is in no hurry to cash in. He considers the ranch ''a canvas'' on which he plans to create America's premier urban community, filled with sumptuous office parks and splendid homes surrounded by luxuriant open spaces. Local opposition, however, wants Irvine's master builder to keep huge portions of his canvas blank. Says one candid Orange County developer: ''The urge among local people to help Don get his second billion is not exactly overwhelming.'' Bren is trying to disarm his antagonists by anticipating their concerns and searching for compromises, even at costs that would make most developers blanch. On a proposed 2,200-acre commercial development called Spectrum, for example, he spent more than $200 million building roads and landscaping the entire site before breaking ground on any of the buildings. ''I try to be harder on myself than any planning board or citizens' group would be,'' he says. Bren can afford his generosity. Left as agricultural land, the Spectrum site would yield $11 million in annual rents. Fully developed, it could generate ten times more. Just how rich Bren and his heirs may ultimately become is unknowable. Estimates of the ranch's value range up to $3 billion, but it will be decades before the property's development is complete. One Orange County builder speculates, only half-jokingly, that when that day comes, Bren's last two undeveloped acres will be worth as much as all the thousands on which he'll already have built.