It's interesting to walk through neighborhoods where "old money" lives -- places like the Upper East Side of Manhattan. If the lights are on in the apartments and the curtains aren't drawn, you can see the chandeliers, the paintings on the walls. Sometimes there will be a party and you will hear laughter drifting out onto the night air and wonder who the people are and who they are telling stories about.

F. Scott Fitzgerald wrote about this world, but always from the outside looking in. Edith Wharton was born into it, but her characters are long dead.

Our best modern novelist of upper-crust manners may be Louis Auchincloss, who died this past January at age 92. Besides his 31 novels and 17 story collections, he wrote biographies of Wharton and Cardinal Richelieu and Woodrow Wilson, a book about reading Henry James, numerous literary profiles, and now this slender memoir, "A Voice From Old New York." He practiced law by day and sometimes wrote while sitting in court. His name is pronounced Awkin-closs.

The Auchinclosses were old money (he was a fifth cousin of Franklin D. Roosevelt, a cousin by marriage of Jackie Kennedy), but by the 1920s they weren't really rich. "One of Father's uncles had married a Standard Oil heiress. Now she was rich." (She had 30 servants.) He writes ironically about how his father "managed" on $100,000 a year, at a time when successful doctors earned $10,000. (At a party once, Herbert Hoover's treasury secretary, Ogden Mills, was asked how much income a person could get by on. He said, "On $50,000 a year you can't even keep clean.")

Auchincloss spent most of his law career looking after immense family estates and trusts, which also meant keeping secrets. A few spill out here, but the most damning portrait is of a class, and of Auchincloss for being loyal to it. He writes about the group sexual habits of Groton schoolboys, about odd social customs among the WASP ascendancy, about upper-class conformity, about rare brushes with less fortunate people. He spent the worst years of the Great Depression away at school, comparing family wealth and connections with the other boys.

In a chapter titled "My Life in Crime," he describes a summer of theft and vandalism while the family was in Maine. Bar Harbor police rounded up the usual suspects, never imagining the culprit was the son of such a "good" family. Money confers all kinds of immunity -- to suffering, obligation, worry, guilt, even treason. While employed at the prominent law firm of Sullivan & Cromwell, Auchincloss helped a subsidiary of J.P. Morgan avoid charges of Nazi collaboration. (It was just business.) But some friends never forgave him when he wrote a novel based on the Richard Whitney embezzlement scandal.

In this memoir he observes the peccadilloes of his class in a detached way, the same way he seems to have lived his life, austerely, sexlessly, like an observant, amused bachelor uncle.

Eric Hanson is an artist in Minneapolis and the author of "A Book of Ages."