Excluded from the city's opportunities, physically, politically and economically marginalized, slum dwellers are particularly vulnerable to crime and violence. They face an acute risk of becoming victims or offenders and live in a state of constant insecurity. Only a few cities have incorporated a coherent component to prevent crime and mitigate violence in their urban development agendas. Impact on urban safety has occurred somewhat unexpectedly. That is the main lesson to be drawn from the pages of this book: urban policy integration.