After vacationing in Vermont for years, Mr. Koren became a full-time resident of Brookfield (population 1,200) in 1982. He joined the volunteer fire department (and was a captain for 30 years) and rode a bicycle nearly every day -- he called it "an addiction" -- through the changing seasons of a peaceful countryside, far from the cares of cities.

"When I ride, I often recall lines from Arthur Conan Doyle" (from "Scientific American" 1896), he said in the interview for this obituary, and he recited them: "When the spirits are low, when the day appears dark, when work becomes monotonous, when hope hardly seems worth having, just mount a bicycle and go out for a spin down the road, without thought on anything but the ride you are taking."