J. Jelles (4-7-1932 / 27-5-2003) grew up in Indonesia. His father was a civil servant and his mother an artist. After returning to the Netherlands he went to TH Delft, where he graduated in 1960 with Van Eesteren and Van den Broek. Entirely in line with his teachers, he remained loyal to functionalist principles. Important source of inspiration, also in a formal sense, was the Nieuwe Bouwen, especially Duiker, whom he greatly admired and whose work, especially Zonnestraal, he brought to his attention again ( exhibition Zonnestraal SM 1962; Forum issue 1972). His work exudes the aesthetics of making through neat, unconcealed use of materials and the clear display of construction. Moreover, in addition to utility buildings, he focused on social assignments, particularly social housing and community centers. He experimented with both traditional (wood) and new materials and constructions. Another important line is the focus on linear growth - typical of the 1960s and 1970s, we also find this theme abundantly with Van den Broek and Bakema - combined with the development of modular floor plans. This led to high-tech-like projects such as the Microcenter in Delft (1972) and the (already demolished) WAVIN building in Zwolle (1972). Also striking in both projects is the unconventional use of materials: a combination of steel (and in the case of WAVIN concrete) and plastic. Also playing through his work is the influence of structuralism, which began its rise just in his student days from Amsterdam. Typical in this respect - especially in early work - is the unconcealed use of wood and (concrete) brick and the configurative coupling of square plan elements. Ultimately, the structuralist influence provides a certain softening of his functionalist vocabulary. In this sense, his work is akin to that of contemporaries such as T. Dijkstra (*1931), W. Röling (*1936), J. Hoogstad (*1930) and C. Dam (*1932), in which the functionalist line is more pronounced than the structuralist one.