?Housing problems are not restricted to the poor. The solutions we want to put forward concern all societies. But since we have to set priorities, emphasis was put on techniques accessible for the poor members of Society. The general problems of housing can be classified into three principal domains: that of social, environmental and technical criteria.? written from the 1970s onwards, roofs collects practical information (tested for unesco by the author himself) on the construction of roofs and shelters, which were intended to meet the material needs of the poor in the global South. It consists of manuals written independent of each other, and is happily representative of the maturity of Friedman, who in those years had already decided to focus his interventions on how to include the inhabitants in the design of their habitat, because ?participation is not spontaneous and cannot be claimed out of the Blue.? while utopie réalisables (literally, ?achievable Utopias,? 1975 ? no English Edition to date) represents the theoretical summa of this intense period, the manuals are the main communicative tool the franco-hungarian architect created, which was aimed at making such Utopias concrete. The manuals are composed of essential ?blackboard? sketches, which can also be read and interpreted by illiterate people ? a feature that convinced Indira Gandhi to print a large number of copies, and also contributed to the establishment of the Museum of simple Technology founded by Friedman in Madras (currently Chennai), in the mid-eighties. In roofs, the author brings to the attention of his readers the fact that the various problems of modern cities are the result of irresponsible attitudes towards the Earth. This thesis was perfectly in line with the thinking of some architects (including Christopher Alexander, Enzo mari, Victor Papanek and Bernard Rudofsky), who at the time, and each in his own way, expressed strong criticism of industrial Society.