All the countries have one thing in common: since the postwar years, they have been confronted with the problem of how to house their millions of inhabitants. The housing need is especially acute in their cities, which have grown much faster than other settlements. In the villages and small towns, people continue to build their own shelters, using local materials and indigenous technologies. In the cities, however, self-built houses are concentrated primarily in festering slums and squatter areas where an increasing number of the poor people live.

The fundamental dilemma is that, on the one hand, the community and government cannot afford the resources commensurate with the housing need, and, on the other hand, the great majority of the urban population is too poor to build adequate housing without public assistance. And in some countries, housing conditions are much worse than they need be as a result of either no policy or misguided policies.