This article originally appeared in the February 2008 issue of Architectural Digest.

One reason business tycoons love Palm Beach, still one of America's toniest and most traditional resort towns, is its impressive inventory of grand mansions from the 1920s. For decades both scions of industry fortunes and the newly rich have gobbled up the Mediterranean-Moorish-Spanish-style piles from the period designed by the area's signature architects, among them Addison Mizner, Maurice Fatio and John Volk.

For some, however, such as one New York couple, these historic houses hold little attraction. Instead, says the wife, "I was ready for Thermopane windows and central air-conditioning. We wanted comfort." They found it in a Mediterranean-style house less than 10 years old. And, as they have done for 25 years, as soon as the couple bought the house, they called Penny Drue Baird, the owner of the New York decorating firm Dessins. "We've done six projects together, including two co-ops on Park Avenue and a beach house in East Hampton—I totally trust Penny," the wife says. "She has the best taste."

Their program in Palm Beach was simple. "I told Penny I wanted it warm and cozy but clean, not cluttered," the wife recalls. "I wanted it tranquil, restful, light and airy. No ruffles and bows." Then she left Baird alone. "Penny knows my style," she says. "I don't believe in micromanaging." So complete was the clients' trust that the wife didn't feel the need to travel to London and Paris to shop with Baird. "Penny e-mailed me photos of antiques she found, and I replied yes or no," the wife recalls.

It's a designer's dream. The house has traditional Spanish touches—a red-tile roof, a stuccoed exterior, handsome arches and lots of stone columns—but the interior was generic and, well, dull.

"First I worry about the architecture, then the decorating," Baird says. She moved doorways, added moldings, put paneling in the ceilings and installed French limestone chimneypieces. "I did not gut the house," says Baird. "I did put more architecture into it."

She was particularly concerned that the spaces flow well, beginning in the entrance hall. "I wanted an elegant entrance to set the stage," she says. It has, for example, a grand piano that is frequently employed at parties. Baird tucked it under the sweeping curved staircase, so guests sitting in the living room can hear it. She placed a five-piece Chinese porcelain garniture on top of the piano and then hung a large Chagall gouache behind it. A wool-sisal rug softens the look of the marble floor, while a French bronze-and-crystal chandelier from the 1880s lends an Old World touch.

She divided the living room into separate seating areas. "I designed a back-to-back sofa so one side looks to the piano and the other to the outside," Baird says. To give the space some character, she paneled and mounted lights in the ceiling. Picasso's 1959 Bacchanalia and de Kooning's 1967 Woman impart gaiety, while the four tall bronze lamps—limited-edition works by Jedd Novatt, an American sculptor living in Paris—provide structure. She judiciously mixed upholstered pieces, including four hand-tufted chairs, with antiques: a Chinese low table, a tall case clock and a pair of imposing painted French cabinets. The room's colors, she notes, "are soft so they don't compete with the view."

That view is pure bliss: Beyond the infinity-edge pool, one sees a palm-lined inlet of the Intracoastal Waterway and a grassy green vista. You could be in the tropics, not on a 14-mile-long island in the middle of Florida.