The view is unbelievable. On a clear day, a customer can see south to the Jersey shore, north to Connecticut, west to the Allegheny ridges and east almost to the Bermuda Triangle. The vantage point is not a mountaintop or a low-flying 747 but a restaurant called Windows on the World. It is an acre in size, cost $7.5 million and is perched 107 stories above lower Manhattan atop the World Trade Center. In its first year Windows is expected to gross $10 million, making it one of the world's most lucrative restaurants. For Joe Baum, 56, who planned it and manages it, Windows also marks an impressive comeback in the volatile chic-food business.

Six years ago Baum resigned as division head of the $100 million-a-year Restaurant Associates, where he had been responsible for such prestigious Manhattan eateries as the Four Seasons. He began to work on Windows in 1970, combining his own experience with the recommendations of his longtime mentor, gastronome James Beard. It opened last June.

Between noon and 3 p.m. weekdays it is a private club, featuring library, sauna, masseur and exercise room for members, plus a "Cellar in the Sky" where they can stash their personal Château Lafite-Rothschilds. Annual dues for the club range up to $420. Nonmembers are allowed in for a $10 cover charge. After 3 p.m. the restaurant is open to anyone at fairly reasonable prices. A prix fixe dinner—Boeuf Madagascar—runs $16.50, not including wine. Would-be diners must be willing to wait. There is a six-week delay for dinner reservations Monday through Thursday; for weekends it's several months.

Most critics agree that patience is amply rewarded. After taking the silent one-minute ride 1,310 feet to the top in a living room-sized elevator, the customer passes through a mirrored green corridor into the gold-and-white main dining room. Among the scores who have already come to feast on the gourmet dishes and the view (without any trouble getting reservations, to be sure) are Princess Grace of Monaco, John Wayne, Henry and Nancy Kissinger, Jackie Onassis and King Juan Carlos and Queen Sofia of Spain.

Baum, whose parents ran a summer hotel at Saratoga Springs, N.Y., decided to be a restaurateur when he was only 14. After wartime Navy service as a supply officer in the Pacific and three years with a Florida hotel chain, Baum was hired by Restaurant Associates in 1953 to run their first "tablecloth" operation—the restaurant at Newark Airport. He rose from there. When business declined during the 1969-70 recession, Baum quit.

In addition to Windows Baum also helped design the 30 or so other restaurants and fast-food shops inside the $900 million World Trade Center. His salary is $125,000 a year, plus a share of the operating profits from Windows and the other concessions.

Each morning at 9 Baum drives his BMW sports car to work from the Park Avenue penthouse he shares with his wife of 32 years, Ruth. He settles into his cluttered "War Room" one floor below Windows, where the walls are papered with reservation lists, table layouts and menus. "He's like a five-star general," says a friend. "I'm a real pain," Baum readily concedes, "but I don't know of any other way to create the best damn restaurant in the world."