AN ACQUIRING EYE.

The Neue Galerie, a museum at Fifth Avenue and Eighty-sixth Street that is dedicated to Austrian and German art, occupies the former home of Mrs. Cornelius Vanderbilt III, and is the kind of place that is usually described as a jewel box: compact, exquisite, and filled with things that conspicuously display the wealth and taste of its owner. That owner is Ronald S. Lauder--the cosmetics heir, businessman, philanthropist, former ambassador, and sometime mayoral candidate--and one recent afternoon he made his way through the museum, checking on the jewels.

It was an hour before the doors were to open for a cocktail party celebrating the latest exhibition--a show of domestic interiors designed by Josef Hoffmann, the Viennese architect, in the early part of the twentieth century--and last-minute preparations were being made. In an upstairs gallery, someone vacuumed specks of dust from the inside of a case that contained examples of Hoffmann's sleek tableware designs; downstairs, waiters were arranging champagne flutes on silver trays. Lauder, who opened the Neue Galerie five years ago and drops by several days a week when he is in New York City, surveyed an austere master-bedroom suite that, in an impressive feat of curatorial persuasion, had been borrowed from a Viennese family, the Salzers, in whose home it remains in daily use. "These people are sleeping on cots," Lauder said, with a note of satisfaction; later that evening, he was to host a dinner for the Salzer matriarch and her son by way of recompense. In another gallery, Lauder stepped into a reconstructed Madchenzimmer--a girl's room, from 1904, with a twin bed, a dresser, and a vanity--and adjusted a curtain hanging from a closet rail, to the mock dismay of the museum's director, Renee Price, who was accompanying him on his tour. "Sir, sir, we take our shoes off when we walk on the felt--it will get marked!" Price cried. Lauder stepped off the carpeting, which appeared unsullied by his trespass. "Well, maybe not by limousine riders," Price conceded.

Lauder, who is the younger son of the late Estee Lauder and is estimated to be worth $2.7 billion, is sixty-two years old. He was dressed formally, as he invariably is, in a monogrammed white shirt and a blue pin-striped suit that was made by hand for him in Milan. He has graying hair, which he wears brushed back from his temples. His eyes are heavy-lidded and lugubrious, his voice low and unmodulated, his smile cautious. He is just under six feet four inches tall, and moves with the self-consciousness of one who, having inadvertently claimed more than his fair share of vertical space, is careful not to dominate the horizontal. When he gesticulates, as he does to express the enthusiasm that his subdued demeanor might otherwise fail to convey, the movement is all below the elbow, like that of a reluctant swimmer splashing waist deep in cold water.

The current object of Lauder's greatest enthusiasm, and the most glittering jewel in his museum, is on the second floor: "Adele Bloch-Bauer I," by Gustav Klimt. The painting was commissioned in 1903 by Ferdinand Bloch-Bauer, a wealthy Jewish Viennese industrialist and the husband of its twenty-five-year-old subject, the flush-faced, sensuous-lipped, richly bejewelled Adele Bloch-Bauer. She was a well-known hostess whom Klimt depicted in a sinuous golden gown and robe, against an abstracted golden background, looking like a Byzantine socialite who has just set down her cigarette holder and is about to discuss the latest symphony by that terribly interesting composer Gustav Mahler.

For sixty-five years, the portrait hung in the Belvedere Palace, in Vienna, which houses the Austrian state's incomparable collection of Klimts, including the artist's most famous work, "The Kiss." Eight years ago, however, Adele Bloch-Bauer's heirs began efforts to reclaim the painting, which Austria had appropriated from Ferdinand Bloch-Bauer during the Nazi era. A year ago, a government panel declared that the painting, along with four other Klimts formerly owned by Bloch-Bauer that had been hanging in the Belvedere, was the property of his heirs, among them Maria Altmann--the ninety-year-old niece of Adele Bloch-Bauer, who lives in Los Angeles. Several months later, while the painting was on display at the Los Angeles County Museum of Art, the news broke that Lauder had bought it, on behalf of the Neue Galerie, for a hundred and thirty-five million dollars--at the time the highest price ever paid for a work of art, surpassing by thirty-one million dollars the previous record, for Picasso's "Boy with a Pipe," in 2004.

Lauder has been a serious collector for decades--he owns about four thousand works--and his discernment is widely admired in the art world. Glenn Lowry, the director of the Museum of Modern Art, says of him, "There are lots of people who can tell the difference between something great and something very good. He can tell the different between great and exceptional." He calls Lauder's private holdings "the finest collection of modern art assembled by an individual in the world today." (For many years, Lauder was the chairman of MOMA, and Lowry's museum stands to profit considerably from the fruits of Lauder's connoisseurship when the time comes.) The Klimt purchase has placed Lauder in the select group of individuals whose desire to acquire superlative works of art has been matched by a willingness to pay any sum to acquire them, a pantheon that includes H. E. Huntington, who bought Gainsborough's "Blue Boy" for seven hundred and twenty-nine thousand dollars in 1921, and Andrew Mellon, who paid eight hundred and thirty-six thousand dollars for Raphael's "Niccolini-Cowper Madonna" in 1928.

The legacies of these men have become beloved public institutions: the "Blue Boy" is the cornerstone of the Huntington Library's art collection, in San Marino, California, and Mellon's collection is the foundation of the National Gallery, in Washington. The Neue Galerie, too, was created not just for the private pleasure of its owner but also for the edifi-cation of the public, and not since Henry Clay Frick bestowed his home and art works upon the city has New York been the beneficiary of so impassioned, meticulous, and prodigal a collector. Lauder has strong pedagogical inclinations--one gets the impression that he would happily stand in his museum all day long, explaining Egon Schiele's use of graphic distortion to bemused Dutch tourists--and for him the portrait of Adele Bloch-Bauer is both a gorgeous object and a historical document of critical importance to the museum's mission. "Klimt's greatest painting is 'The Kiss,' which I also love," Lauder told me one day. "But Ferdinand and Adele personified Vienna at that time. The ...