iii 3.1 Classic urban greening -'the city beautiful' -in downtown Vancouver, Canada (Photo © David Simon) 3.2 The humid tropics facilitate natural urban greenness, although often blended with well-maintained gardens, as here in a hillside high income area of Kampala, Uganda (Photo © David Simon) 3.3 Even in the humid tropics, high density, low income areas often lack the greenery of high income areas, with exposed brown earth reflecting a lack of investment and maintained public spaces, and sometimes also livestock grazing pressure. The multi-purpose value of trees, like this one planted as part of an action research project in peri-urban Kumasi, Ghana, is therefore high (Photo © David Simon) 3.4 Intensive peri-urban agriculture, Lagos, Nigeria (Photo © David Simon) 3.5 Conservation of ground cover on steep slopes and of some vegetation in and around informal settlements maintains slope stability, intercepts storm run-off and improves soil penetration by rainwater. These valuable ecosystem services are vital for poor and wealthy alike, as here in peri-urban Durban, South Africa, in the context of extreme events and climate change (Photo © David Simon) 3.6 Green walls and balcony or roof gardens, as here in Manhattan, New York City (USA), are aesthetically attractive and important for carbon sequestration (Photo © David Simon) 3.7 Green infrastructure: the Hudson River Park on Manhattan's Lower West Side, which replaced derelict wharves and warehouses, has provided valuable green shade and recreation space, and increased urban biodiversity and carbon sequestration capacity (Photo © David Simon) 3.8 Nanjing (People's Republic of China) exemplifies urban infrastructural greening as part of comprehensive redevelopment to tackle industrial pollution and unsustainable urbanism (Photos © David Simon) 4.1 Different life prospects: City traders, London; second-hand clothing vendor and customers, Maputo; beggar, Copenhagen, respectively (London and Copenhagen