Silvio Laccetti was cleaning out his office after 43 years of teaching at the Stevens Institute of Technology, a science and technology school in Hoboken, New Jersey, when he stumbled across a pile of unreturned reports, assignments and examinations from some of the thousands of students he had taught over the years.

It gave him an idea: invite some of his best former students for dinner. Not all at once, however: one at a time.

What Dr Laccetti, who taught history, called his “retirement odyssey” involved 83 dinners and lunches consumed over three and a half years with 104 of his one-time students, mostly individually but a few in small groups.

He spoke by phone with another dozen who lived too far away to meet in person.

The odyssey gave him an opportunity academics seldom get: to measure his impact on the world.

“They had listened to my advice,” Dr Laccetti, 72, said. “They maintained an interest in the humanities. They even talked about me to their kids, and taught their children some of the things that I taught them.”...