Almost 1 billion people, or 32 per cent of the world’s urban population, live in slums, the majority of them in the developing world. Moreover, the locus of global poverty is moving to the cities, a process now recognized as the ‘urbanization of poverty’. In the United Nations Millennium Declaration, world leaders pledged to tackle this immense challenge, setting the specific goal of achieving ‘significant improvement in the lives of at least 100 million slum dwellers by the year 2020.

This means addressing not only the needs of slum dwellers for shelter, but also the broader problem of urban poverty, especially , unemployment, low incomes and a lack of access to basic urban services. . The report proposes an operational definition of slums and, on this basis, provides the first global estimates of the numbers of urban slum dwellers. It discusses the local, national and international factors underlying the formation of slums. It analyses the social, spatial and economic characteristics and dynamics of slums. And it assesses the impact of the main policies towards urban slums adopted by governments, civil society groups and international organizations.