Our epoch is witnessing a world-historic shift in human habitat: for the first time, more than half the global population will soon be city dwellers, in one form or another. The small-scale settlements that have been the cradle of peasant work and life for many thousands of years—the myriad villages, compact or dispersed, spread out across the countryside—are no longer home to the majority of mankind. The massive expulsion of labour from agriculture, accelerating over the last half-century, has been accompanied by an exodus from the villages. At present, 3.2 billion people are congregated in towns and cities. Their number is expected to grow to 10 billion in the middle of this century. This gigantic shift is mainly taking place in the zones of the South: within the next two decades, metropoles such as Jakarta, Dhaka, Karachi, Shanghai or Mumbai will each have 25 million inhabitants or more.

Urbanization is not, of course, a new phenomenon. The push out of agriculture and the trek from the countryside are well known themes in 19th and 20th-century western history. Up to the mid-20th century, however, that migration resulted—if not immediately, then within a relatively short space of time—in regularized employment in the mills, docks, construction industry, public-sector enterprises or other large-scale and labour-intensive worksites, or else in domestic service. Another route out of village life was through emigration to countries that were still struggling with under-population. Economic refugees fleeing from Europe were welcomed as colonists in these settler states, reputed for their perseverance and enterprising spirit. They brought to these ‘empty’ territories the labour power required to valorize vast new tracts of natural resources. Up to thirty years ago, the assumption was that this transformation from an agrarian-rural to an industrial-urban mode of production would be duplicated in the ‘backward’ parts of the world. But the notion of industrialization as the handmaiden of urbanization is no longer tenable. This goes a long way to explain why huge numbers of the new arrivals to the city are slum-dwellers, and are likely to remain so throughout their lives.

How and why this is happening is the story graphically told in Mike Davis’s new book, Planet of Slums. While many case studies have described what it means to reside in a favela, basti, kampung, gecekondu or bidonville, Davis provides a properly global portrait, setting such shanty towns in comparative perspective.And whereas urban specialists have focused on questions of space and land use in their discussions of slums, and developmentalists on the issue of their ‘informal’ economies, Planet of Slums commands our attention as a broader historical synthesis of the two. Drawing on the ‘global audit’ provided by the un’s 2003 ‘Challenge of the Slums’ report, Davis outlines the scale of world urban poverty today: Mumbai, with 10 to 12 million squatters and tenement dwellers, is the global capital of slums, followed by Mexico City and Dhaka, with slum populations of 9 or 10 million, and then Lagos, Cairo, Karachi, Kinshasa-Brazzaville, São Paolo, Shanghai and Delhi, with around 7 million each. If the largest mega-slums—contiguous zones of urban poverty—are in Latin America (an estimated 4 million living in Ciudad Nezahualcóyotl, Chalco, Iztapalapa and other south-eastern municipios of Mexico City; over 2 million in the Caracas shanty town of Libertador, or the El Sur and Ciudad Bolívar districts of Bogotá), the Middle East has Baghdad’s Sadr City (1.5 million) and Gaza (1.3 million), while the corrugated-iron shacks of Cité Soleil, in Port-au-Prince, and Kinshasa’s Masina district each hold half a million souls. India has nearly 160 million slum-dwellers, and China over 190 million. In Nigeria, Pakistan, Bangladesh, Tanzania, Ethiopia and Sudan, over 70 per cent of the urban population lives in slums.

The laudable ambition of Planet of Slums is to propose a historical overview of the global pattern of these settlements; one that will provide, as Davis puts it, ‘a periodization of the principal trends and watersheds in the urbanization of world poverty’ in the postwar period. Broadly speaking, he discerns an initial acceleration of Third World urbanization in the 1950s and 1960s, with the post-Independence lifting of colonial pass laws (especially in sub-Saharan Africa), the ‘push’ of civil war and insurgency (Latin America, Algeria, Partition India, Southeast Asia) and the ‘pull’ of employment opportunities offered by import-substitution industrialization policies (Latin America, South Korea, Taiwan). Davis documents what he terms the ‘treason’ of Third World states in failing to provide housing for their new urban workers, as post-Independence governments (in Africa and South Asia) or dictatorships (in Latin America) abdicated responsibility for the poor to rule in the interests of local elites.

But the ‘Big Bang’ of urban poverty comes after 1975, with the imposition of imf-World Bank Structural Adjustment Programmes which ‘devastated rural smallholders by eliminating subsidies and pushing them to sink, or swim, in global commodity markets dominated by heavily subsidized First World agribusiness’. At the same time, the saps enforced ‘privatization, removal of import controls . . . and ruthless downsizing in the public sector’. And they were accompanied by the 1976 switch of imf-World Bank policies—under the joint influence of Robert McNamara and former anarchist urbanist John Turner—to ‘self-help’ slum-improvement schemes in place of new house-building, representing, in Davis’s words, ‘a massive downsizing of entitlement’, which soon hardened into neoliberal anti-statist orthodoxy. The net result has been a gigantic increase in urbanization ‘decoupled from industrialization, even from development per se’.