When Brooke Russell Astor died in 2007 at the age of 105, the big question in the press and among individuals was, “Who will be the next Mrs. Astor?” The answer seemed obvious to me. No one. Not just because almost no New Yorker has the verve, insights, or sense of discipline and obligation to those less fortunate than herself, but that life and the world she had lived in for more than a century had almost vanished. Today, copycats seem vulgar in their imitation of grandeur. And the tsunami of a celebrity culture that creates icons has swept over America. In this callow atmosphere, Brooke Astor would never be an icon, but she is remembered with nostalgia.

Last week at a Sotheby’s estate auction, Astor’s tortoise-shell-and-diamond cigarette case embellished with a baron’s coronet was estimated to sell at $700 to $900. It brought a respectable but hardly iconic $6,250. That is about the same price—or less—than one might pay for a similar item at Fifth Avenue’s A La Vieille Russie.

At the auction of her estate at Sotheby’s in 1996, Jacqueline Kennedy’s (most people overlooked the Onassis) silver cigarette box was estimated to bring $250 to $300. It went for $18,400. In 2011, Marilyn Monroe’s dress from The Seven Year Itch fetched $5.5 million at auction. Michael Jackson’s Thriller jacket sold for $1.8 million. These three people were icons of the American celebrity culture.

For the Astor auction, Sotheby’s had gone all out with a catalog that weighed more than eight pounds, but for me, that tenth-floor viewing room held only ineffable sadness. What once had the mystique aspired to by elite women now seemed just stuff. Seventy-three genre pictures, most of dogs, a great deal of bric-a-brac and chinoiserie, even beds and bedding, the possessions of Mrs. Astor and all she represented on the surface were now to fall under an auctioneer’s gavel.

I knew Brooke Astor for more than a quarter of a century. She had approached me after a New York Public Library trustees meeting and complimented me lavishly on one of my books. She asked a few trenchant questions. Then she said, “Would you care to come for tea?” Would I? Of course I would. After that there followed invitations to grand lunches and coveted dinners, small gatherings, and “just us two” ones.

Soon I discovered that the private Mrs. Astor was a maverick. At a dinner party she gave for Schuyler Chapin, when he had just become commissioner of cultural affairs for New York City, he stood and said, “I can never understand how I, who never went to college, am now commissioner of cultural affairs.” At which point Brooke piped up, “Well, Schuyler, neither can we.” At library meetings of the nominating committee, Brooke exhibited what my mother used to call “steel under velvet.” At one such meeting, the name came up of a vastly wealthy person, who I doubt had ever read a book. Everyone seemed dazzled by the money, but when it got to Brooke she said, “I understand perfectly why this person would benefit the library monetarily. If you wish to elect him to the board, that’s fine with me. I have only one caveat, I would have to resign.” Over the years, Brooke voted against two other wealthy men as well, one because when she and her beloved Vartan Gregorian had gone to his office to ask for a library contribution, he sat with his feet on the desk and never rose to greet them. The second she later told me in private, “Because he smokes cigars in the elevator"—they then lived in the same building—"and uses four-letter words.”

Within her own orbit, Brooke had a way of getting to the point. After hearing a pro-life speech, she remarked that she didn’t understand the whole abortion debate. “In my day, we called it a D&C [dilation and curettage]. I had several myself.”

When my husband, after contracting prostate cancer (that went unknown and untreated for several years) up and left me and his friends to live in Aspen, divorce, and see himself, in his vision, reborn like Botticelli’s Venus on the Half Shell, everyone commiserated with me—“Oh, poor Barbara.” That is, everyone except Brooke, who invited me to a “just us two” lunch. “I wanted to see you,” she said, “to tell you that you are the luckiest person in the world, you’ve avoided all the nurses around the clock, the bed pans, the isolation, the misery. I know, I watched Vincent die. Now you can walk away with your head held high and go about your life.” I held that thought close to me in the next two years before he died.

At that point, Brooke left the room, returning shortly with a very small sparkling Judith Leiber modiliére, and handed it to me. “Every time you start feeling sorry for yourself,” she said, “just look at this absolutely ridiculous frog and it will make you smile.” It does.

Some said Brooke was vain. She altered the age on her passport into her eighties. At her 90th-birthday party, my attractive male friend became the object of her attention. Later he commented, “What a seductress she is. I would have carried it further, but I was afraid she’d break.”

Finally, came the dark days. “I think I’m going gaga,” she told me. Then a lunch where she repeated, “My mother told me never get above yourself, Brooke,” several times. Or a rainy day when Catherine Dunne came running up to me at the New York Public Library and said Brooke had left the building, not in her car, but walking and no one knew where she was. I drove around until I found her and said I’d like to give her a lift. “How dear,” she replied and came into the car. David Rockefeller escorted her out of her 100th-birthday party early (before the elaborate dessert) presumably assuming that it all was too much for her. Or the terrible day when she asked me, “Are you Barbara Goldsmith or Barbara Walters? It’s very hard to remember.” The days grew worse: the broken hip, the six weeks in the hospital. The beloved dog who bit off the tip of her finger. The seminal moment when her son, Tony Marshall, fired her beloved butler, Christopher Ely, and the scandal she would have done anything to avert.

Brooke Astor had lived for more than a century—a century marked by progress and strife. She told me that she was about to sponsor a Modern Library edition of The Education of Henry Adams, a book published privately for his friends in 1907 and publicly after his death in 1918. “Why did you choose that of all books?” I asked her. “Oh,” she replied, “because I knew him. He was a friend of my parents and came to my 12th-birthday party.” Brooke remembered the sinking of the Titanic. She was 10 at the time. And she lived all the way through September 11, 2001, when she called her dearest Annette de la Renta (“She’s like a daughter to me”) to express her anguish.

Although the press wrote that the auction raised nearly $19 million for Astor’s favorite charities, $10 million over the estimate, I thought, seeing that only three of the pieces accounted for $4 million, that the prices were good but not spectacular.

In the last session, Brooke’s jewelry was auctioned off. I was sure that, if nothing else, her jewelry, especially her famed emerald necklace, would bring iconic prices. There was an exciting moment when the emerald ring Vincent had given her in lieu of an engagement ring estimated at $100,000 to $150,000 went for $1.2 million in a mano-a-mano between a couple in the audience and a phone bidder.

The auction’s last session was now running an hour and a half late, well into the Jewish holiest of holidays, Yom Kippur. Some people were leaving the bidding room when Brooke’s fabled emerald necklace came under the hammer. It was estimated at $250,000 to $350,000 (less than the worth, a Sotheby’s expert told me, of the 27 emeralds alone). Vincent Astor and Brooke had selected every gem. It was his last gift to her. The necklace sold for $686,500. It was a good, but hardly iconic, price. Personally, I don’t want to see anyone wearing that necklace. For me, it belongs to Mrs. Astor forever.