The death of the industrial designer Niels Diffrient as noted by this New York Times obituary is still hard to believe, given his vitality and productivity at 84. I've already noted here how many architects remain active into their eighties and beyond. The prodigious Viktor Schreckengost made it to 101.

I spent hours on the telephone with Diffrient when I wrote the chapters on chairs in Our Own Devices; his Jefferson Chair, fittingly displayed in the Times, was the most expensive production office seating in the world in the 1980s boom, and Diffrient explained that his original manufacturer had gone out of business in the crisis of 1987 and that he hadn't been able to find another willing to take a license.

What I'll remember most about his work is not that product but his brilliant solution to the Achilles heel of many contemporary office chairs with the mesh backs made popular by Don Chadwick and Bill Stumpf's 1994 Aeron Chair -- absence of lower back support. The Aeron's manufacturer, Herman Miller, sells a "sacral-pelvic stabilizer" as an option, but in all the offices I've visited (and in the Aeron-equipped reading room of the New York Public Library's Science and Business division) I've never actually seen one.

I was able to try Diffrient's elegant approach in Humanscale's Diffrient World Chair -- not adding a separate pressure device to the mesh chair back but cutting the mesh in panels and assembling them to give the back a firm three-dimensional shape. This was a centuries old concept, taken from tailors' cutting cloth to make form-fitting garments. Humanscale offers a variant of the concept in its Liberty Task Chair.

Producing such chairs needed more than a eureka moment of taking a concept from fashion to furniture. An office chair, used eight or so hours a day, is a severe test of materials and assembly techniques. Some visually striking ideas can fall apart under even moderate use or turn out to be much less comfortable than they look. Diffrient did his own prototyping and testing and worked for months with engineers to get essential details right. No computer design program alone can simulate that experience. (There's an excellent interview here.)

And where did tailors learn the technique that Diffrient borrowed? It was one of the great unsung innovations of the Middle Ages: body-fitting plate armor needed a padded layer constructed by a new breed of artisan, the linen armorers, the pioneers of suit construction.

Niels Diffrient should thus be celebrated as the latest of a succession of masters finding new ways to adapt the material world to our bodies and to relieve us of some of the burden of doing the reverse.