In contemporary European and American urban policy and politics and in academic research it is typically assumed that spatial concentrations of poor households and/or ethnic minority households will have negative effects upon the opportunities to improve the social conditions of those who are living in these concentrations. Since the level of concentration tends to be correlated with the level of spatial segregation the 'debate on segregation' is also linked to the social opportunity discussion. This book explores the central questions in urban and housing studies: Do poor neighbourhoods make their residents poorer?Does the neighbourhood structure exert an effect on the residents (behavioural, attitudinal, or psychological) even when controlling for individual characteristics of the residents? This issue has offered a locus for multi-disciplinary investigations on both sides of the Atlantic, and this volume demonstrates the rich geographical, sociological, economic and psychological dimensions of this issue. This book was previously published as a special issue of the journal Housing Studies.