Niels Diffrient studied aeronautical engineering at a technical college in Detroit from 1943 until 1946 before studying at the Cranbrook Academy of Art in Bloomfield Hills, Michigan, from 1948 until 1953. While still a student at Cranbrook, Niels Diffrient also worked as a designer and model-maker in Eero Saarinen's practice. In 1954 Niels Diffrient was awarded a Fulbright Scholarship for a year's study of design and architecture in Italy. While in Italy, Niels Diffrient worked in Marco Zanuso's practice. From 1956 until 1981 Niels Diffrient was an employee of Henry Dreyfuss Associates in New York. At Dreyfuss Associates, Niels Diffrient designed airliner cabins for Hughes, Lockheed, and Learjet as well as medical equipment for Litton Industries and others. While working for Dreyfuss Associates, Niels Diffrient was already preoccupied with compiling anthropometric data, which he published jointly with Alvin R. Tilley as "Humanscale 1-2-3" (1974), "Humanscale 4-5-6", and "Humanscale 7-8-9" (both 1981). From 1981 Niels Diffrient was self-employed; he opened Niels Diffrient Product Design in Ridgefield. Even before he did so, Niels Diffrient had designed office furnishings and once he established his practice, devoted himself entirely to this task, designing office furniture for Knoll International and Sunar-Hausermann. Niels Diffrient is viewed as one of the most important designers of office seat furniture. His ergonomic studies led to seating concepts for innovative office-chair design. The Niels Diffrient "Diffrient Advanced Management" office chair and the "Humana" seating system date from 1979. In 1980 Knoll the "Diffrient Operational" chair, which adapts to the body of the person sitting in it. The 1982 Niels Diffrient "Helena" (for Sunar-Hausermann) can be adjusted to multiple positions so that it adapts to individual poster as needed. In 1983 Niels Diffrient developed the "Jefferson" office armchair, for Sunar-Hausermann. The "Jefferson", too, can be adjusted to accommodate all postures and can even be used in a prone position. At the same time, this seating concept comprises what might be called an integrated, mobile workplace since it includes various attachments, where users can set a computer, keyboard, or telephone.