Niels Diffrient is a pioneer of ergonomic design -- taking the radical approach of examining the human body as it interacts with furniture, and asking, Is there a better way to sit? His three-volume reference work, Humanscale, explores the relationship of spine to chair and other "human engineering" data necessary for highly specialized workplaces such as a cockpit or a truck cab, as well as aiding in the search for the perfectly comfortable place to sit down.

In the 1990s, Diffrient turned his attention to the office task chair. Working with the company Humanscale, he drew up the Freedom chair, a self-adjusting chair that mixed advanced materials (such as a gel seat pad) with good old-fashioned sketchbook design. The Freedom chair was part of a late-'90s revolution in design that turned expensive ergonomic office chairs into dot-com covetables. In 2004, Diffrient and Humanscale released the lighter and lower-priced Liberty task chair.