Book excerpt: This book looks at slums and social exclusion in the four major megacities of India and Brazil, and analyzes the interrelationships between urban policies and housing and environmental issues. The challenges posed in Delhi, Mumbai, Rio de Janeiro and Suo Paulo have spurred public reformers into action through housing, rehabilitation and conservation programs. Civil society and the inhabitants of these cities have also begun to get involved. On the other hand, one must wonder whether these challenges were partly created by the deficiencies of these very reformers and civil society, be it their lack of intervention (as advocates of government intervention would argue), or the flaws and inadequacies of their actions (as supporters of the free market would suggest). Are policies alleviating or aggravating social exclusion This book explores these questions and more.