Mr. Hotchner described “Aaron Broom” as a project to carry him through the year he turned 100, unless it was the year he turned a mere 97 — more about that later. “I wanted to make it a jolly affair,” he said of the book, “something that would celebrate the fact that you could get as old as I had gotten and, to my vast surprise, still have some of my pebbles on the beach.”

Now, again from across the room, came another revelation from Ms. Kiser: “Hotch had an eye removed three years ago.” During cataract surgery, he said. Actually, he still has the eye, but no sight in it. Hemingway would be wearing an eye patch if it had happened to him, no doubt.

About those friendships. Mr. Hotchner knew J.D. Salinger (in Greenwich Village, before Mr. Salinger moved to New Hampshire) and Tennessee Williams (in college, when the not-yet-famous playwright went by Tom). And writers like David Halberstam and Gay Talese. And the editor Nan A. Talese, who published “Aaron Broom” this July (and is married to Mr. Talese). And the crowd from Elaine’s, the Upper East Side celebrity hangout that was as much a salon as a saloon before it closed in 2011.

He was also present at the creation of the vat of salad dressing that inspired Newman’s Own. Mr. Hotchner had met Paul Newman when he worked on an adaptation of the Hemingway story “The Battler” for television in the fall of 1955. The star was to have been James Dean, but he was killed in a car crash less than a month before the program was to go on the air, live, on NBC. Mr. Newman was cast to replace him. The New York Times’s review of the program said Mr. Newman “had to surmount grotesque makeup, but was quite effective.”

He and Mr. Hotchner both bought houses in Westport in the 1950s. The salad dressing came along later — Mr. Newman would make a batch at the holidays, pour it into wine bottles and drive around the neighborhood, leaving bottles at friends’ houses. At holiday time in 1980, he called Mr. Hotchner, and together they made an unusually large batch, so much they had to find something to stir it with. Mr. Newman came up with a canoe paddle. They also came up with the idea for a company that would sell salad dressing and give the profits to charity.