What should one expect in a Gilded Age biography? A narrative of greed, shallowness, materialism, corruption, unscrupulous individualism in an age of fantastic economic speculation during the post-Civil War boom, ending (more or less) in the early 1900s with the rise of Progressivism and the presidency of Theodore Roosevelt.

“And always the same 400” — to quote Sugar Kane Kowalczyk, better known as Marilyn Monroe, in “Some Like It Hot.” That number represented the upper limit of the best society that Caroline Astor could accommodate in her ballroom. This is the world of Edith Wharton, in which Newland Archer works on Wall Street but never seems to work because he is part of a leisured high society still visible in her novel “The Age of Innocence,” and in films like “The Philadelphia Story,” featuring Katharine Hepburn’s tony accent, and Cary Grant’s confection of a British/mid-Atlantic dialect.

Indeed, in “Some Like It Hot,” Junior (better known as Tony Curtis) parodies Grant in order to convince Sugar that he is a millionaire playboy. Junior is also Geraldine — that is, Jerry, a man in drag escaping the wrath of Spats Columbo (George Raft), because Jerry and Daphne (Jack Lemmon, Mr. Curtis’s partner-in-drag) are witnesses to the St.Valentine’s Day massacre.In other words,the characters are playing characters.It is all a sham.

Similarly, Caroline Astor transformed herself into a character, “Mrs. Astor,” greeting guests in front of her portrait, as if she represented one of a kind, when in fact she was competing with other Mrs. Astors for the title of queen of society. And she married into a family of pretenders,people who tried to establish a royal genealogy, even though they were descended from a fur trapper, John Jacob Astor, the son of a German butcher who became a Manhattan real estate mogul and the wealthiest man in America.

By the time of Prohibition,the Gilded Age was only a memory, and yet its impact lingered. In “An American Tragedy,” Justin Kaplan reminds us in “When the Astors Owned New York” (Viking,196 pages,$24.95),Clyde Griffiths looks up at the gilded ceiling of a Kansas City hotel and decides that he will use any means necessary to become part of that glittering world. Mr. Kaplan, a dazzling stylist, is perfectly suited to his subject: what Henry James lovingly called “hotel civilization.” The Astors built hotels that were “temples of pleasure and theaters of culture,”Mr.Kaplan writes.He often quotes James, who became rhapsodic about hotels like the Waldorf-Astoria (the original one, which opened in 1897, where the Empire State Building now stands) that gave him a glimpse of “perfect human felicity.”

The first American luxury hotels had all the conveniences — telephones, private bathrooms, massage parlors, you name it.The hotels became worlds in themselves; eventually they became subjects of films such as “Grand Hotel.” The hotels were all about the worship of wealth,even for those who otherwise did not have access to such sybaritic salons.

To fully appreciate “Archie and Amélie” (Harmony, 340 pages, $25.95), I’d recommend first reading “When the Astors Owned New York.”Although Donna Lucey does provide historical background, explaining Armstrong (Archie) Chanler’s place in the Astor wealth line while evoking the world of old Virginny that Amélie Rives celebrated in her novels and plays, Mr. Kaplan does a better job of explaining why such figures continue to fascinate us.

Archie wanted to do good while doing well, and like other sons of wealth during the Gilded Age, he had some success not only endowing fellowships for artists but also in business, establishing a North Carolina industrial complex. Amélie, often described as a precursor of Kate Chopin, published a bold, psychological novel, “The Quick or the Dead?” (1888), about a woman torn between loyalty to her dead husband and her attraction to a cousin who resembles him.The novel was controversial because it dealt so openly with a woman’s sexual feelings. The beautiful Amélie played the part of the siren well, enchanting both Henry James and Thomas Hardy.

Amélie had other popular literary successes, but she never produced another groundbreaking work. Instead, she became a user, shamelessly exploiting Archie’s love for her even as she carried on with other men. Archie’s marriage to Amélie scandalized the Astors, who quickly discerned that what she really wanted was to use the Astor fortune to refurbish her family’s crumbling Virginia estate.

The Astors committed Archie to an insane asylum after he became distraught over Amélie’s adultery and his family’s animosity.Ms.Lucey establishes a good case in his defense. He was certainly no stranger than other Astors. But they were disturbed because Archie did not concentrate on his Manhattan real estate holdings, and they feared the loss of the family fortune. He bought his own Southern estate to be near Amélie, rather than staying at his ancestral homes in New York and Newport. Ironically, Archie (who does not figure in “When the Astors Owned New York”) was pursuing the Astor agenda, the one that ultimately whisked William Waldorf Astor away from his forebears and all the way to Britain, where, after decades of trying, he finally won a title and the privilege of sitting in the House of Lords.

To William Waldorf’s son, the title was an imposture. He implored his father to give it up. Of course William Waldorf would not, and to pile irony upon irony, his disapproving son, the second Lord Astor, married a Virginia aristocrat, Nancy Langhorne, who became Lady Astor and also the first female member of the British Parliament. She was a conservative who championed women’s rights.She is perhaps most famous for her exchange with Winston Churchill,himself the product of a marriage between a Brooklyn girl (Jenny Jerome) and Lord Randolph Churchill. Although Nancy and Winston were members of the same political party, they despised each other — as only those on the same side (like the acrimonious Astors) know how to do. “If you were my husband,” Lady Astor told Churchill, “I’d give you poison.”

“If I were your husband,” Churchill replied, “I’d take it.”

Even a conservative like Nancy Astor knew that the first Lord Astor was pursuing a phantom when he removed to Britain and attempted to recreate at Cliveden the aristocratic environment of an earlier age. No sooner did she inherit Cliveden than Nancy set about dismantling that medieval monstrosity, replacing what she called its “splendid gloom” with a more modern ambiance.

Thorstein Veblen, whom everyone writing about the Gilded Age has to quote, used the phrase “conspicuous consumption” to encapsulate the mentality of people who wanted not merely to be rich but to be observed as loaded. Here the biographer in me perks up, because Mr. Kaplan’s narrative suggests that in the Gilded Age, the nature of biography itself changed:

Rich, famous, beautiful, and fashionable men and women, whose daily lives had in the past been led in private, were now to be seen enjoying the pleasures of ornate function rooms exposed to public view. Bathed in the full glare of attention, these rare creatures, the subject of news and gossip stories, were on display for ordinary citizens to observe and maybe learn from as part of their own education in polite customs and demeanor, all of this and more in preparation for a prospective climb up the ladder.

Certainly there were Astors like William Waldorf who hated the attention, but he never acknowledged that his own ostentatious antics actually fostered the hotel-movie-novel civilization he professed to deplore.

These two splendid books are about a bygone age that has not quite gone away, in part because it gave rise to an appetite for biographies that constantly cross the line between the private and public, not content with merely admiring gilt.

crollyson@nysun.com