Philanthropist, Heiress, Collector. Mrs. Ryan, known as Nin, was a daughter of the financier Otto Kahn, a turn-of-the-century multimillionaire who became a benefactor of the Metropolitan Opera even though the Met at first would not assign him a box in its "diamond horseshoe," where rich New Yorkers hobnobbed at intermission. She joined the Met's board in 1956, and after the company moved to Lincoln Center in the 1960's and announced that it was facing a financial crisis, she worked on an emergency fund drive to raise $3 million. She became an honorary director in 1981. Mrs. Ryan was also an art collector whose French Impressionist paintings hung on the walls of her triplex apartment on the East Side of Manhattan and, in summers when she went to London, in the Metropolitan Museum of Art. Mrs. Ryan was born on July 4, 1901, at Cedar Court, Kahn's mansion in Morristown, N.J. Kahn's biographer John Kobler wrote that he was closer to her than to his other children. Father and daughter, Mr. Kobler wrote in "Otto the Magnificent" (Scribners, 1989) "golfed together, rode together, swam together, chaffed each other, went to the opera together, and when apart, corresponded frequently." Sometimes their correspondence included long poems. He signed his "Fathie." When she was in her 20's, she met and married John Barry Ryan, who was working as a reporter for The Newark Ledger. It was a union of financial dynasties: Mr. Ryan was a grandson of Thomas Fortune Ryan, a Virginian who migrated to Wall Street in the 1870's and made millions in railways, tobacco and insurance. He was said to have been the largest single owner of diamond fields in the Belgian Congo. The wedding took place at Kahn's Fifth Avenue mansion on Feb. 9, 1928. Mrs. Ryan called her husband "Johnny" and her father declared, "It is my deliberate conviction that you are the nicest girl in this here republic." Kahn added, in a letter mailed after she had been married for a year, at a time when she and Ryan were vacationing in Palm Beach, "I should love to be with you in the pink palazzo by the southern sea, but there is really no sense your being in this relentless city, because during the day the evil spell of the office claims me." Kahn was a power at the Met until a few years before his death in 1934. Mr. Kober wrote that when Kahn first became involved with the company, the Met had an unwritten rule that no Jew could own a box. He was finally permitted to buy one, in the "diamond horseshoe," 17 years after he had joined the board. The Kahns had Margaret baptized at an Episcopal church in Morristown in 1911, along with her older sister, Maud, and her younger brother, Gilbert. In 1951, two years after Mrs. Ryan's mother, Addie, died, Mrs. Ryan and the other Kahn heirs sold Rembrandt's "Portrait of a Young Student" for $90,000. They gave the money to the Metropolitan Opera. The Met put up a plaque, first at the old house on Broadway and later at Lincoln Center, that said the money had made possible new productions of Verdi's "Don Carlo" and Mozart's "Cosi Fan Tutte." The "Don Carlo" was Rudolf Bing's first production at the Met. Among the other productions to which Mrs. Ryan contributed was the 1960 revival of "L'Elisir d'Amore," by Donizetti. Five years ago, one of her paintings, "The Bench" by Manet, was sold at auction for $16.5 million. Manet's account book showed that the 1881 view of a garden was first sold for 2,000 francs to the Paris dealer Durand-Ruel, who sold it a year later to a Paris stockbroker for 2,500 francs and bought it back 10 years later for 6,000 francs. The painting remained in the dealer's hands until the Ryans bought it in 1945 for an undisclosed sum.