The phenomenon of participatory architectural design is thought to have emerged in the late 1960s and 1970s in Europe. In 1969, Giancarlo De Carlo, one of its main advocates, presented a manifesto in which he asserted that ‘architecture is too important to be left to architects’, criticised architectural practice as a relationship of ‘the intrinsic aggressiveness of architecture and the forced passivity of the user’, and called for establishing ‘a condition of creative and decisional equivalence’ between the architect and the user, so that in fact both the architect and the user take on the architect’s role. He also argued for the ‘discovery of users’ needs’ and envisioned the process of designing as planning ‘with’ the users instead of planning ‘for’ the users.1 In the same year, De Carlo began working on a housing estate in Terni, Italy that involved future dwellers in design decisions. Among other participatory projects carried out around that time were Lucien Kroll’s medical faculty building for the University de Louvain (1970–6) and Ottaker Uhl‘s Fesstgasse Housing, a multi-storey apartment block in Vienna (1979).