The concept of “adequate housing” is slowly but surely becoming internationally accepted as a basis for policies and programmes aimed at addressing the needs of low-income communities. The first part of the guide presents concepts essential to understanding low-income housing, and explores the reasons behind the serious lack of decent, affordable housing in cities and hence the problem of urban slums. Key approaches to addressing the housing needs of the urban poor are outlined next, by examining alternative strategies for what to do about existing slum conditions and informal settlements, and how to avoid future slums through the production of new housing. Finally, the guide examines the main considerations needed to address the improvement of informal settlements and production of adequate and affordable low-income housing on a city-wide scale.