For the first time in history, more people live in cities than in the countryside. Today, one billion people live in an urban slum. Fleeing rural poverty, they can find no affordable housing in the cities and so create their own from whatever is at hand, even cardboard. This is the story of people living on the fringes of Manila, Nairobi, Mexico City, Bangkok, and Cairo. It tells about their worries and concerns, their family life, and their smiles in the midst of their struggles to live on less than $2 per day. These very human and moving stories are interwoven with analysis of the causes and effects of urbanization, including problems of land rights and human rights, poverty, prostitution, the informal market economy of urban slums, and the lack of basic human services.