Don Chadwick studied industrial design at the University of California Los Angeles until 1959. In 1964 he opened a design practice and from 1974 collaborated with office furniture makers Hermann Miller. For Hermann Miller Don Chadwick designed the "Modular Seating" system of upholstered furniture in 1974, which consists of five, simple, cloth-covered modules that can be endlessly combined to make sofas. At that time Bill Stumpf was assistant director of the Hermann Miller research division. Don Chadwick and Bill Stumpf collaborated on developing "Ergon" (1970-1976), an office chair that set new standards of ergonomic seating. In 1977 they opened Chadwick, Stumpf & Associates, a design agency in Winona, Minnesota. Don Chadwick and Bill Stumpf continued to develop highly innovative office chairs for Hermann Miller. In 1984 they developed "Ergon" further as the "Equa" office chair with a flexible back that made this chair even more comfortable to sit on. In 1992 Don Chadwick and Bill Stumpf developed the "Aeron" chair with a seat and back made of breathable, posture-conforming polyester fabric. Since this chair did not have to be elaborately upholstered, production time was considerably reduced.