The present book brings together a series of studies that were developed between 2008 and 2015 by a group of Portuguese researchers from the Nova University of Lisbon and the Lisbon City Council and with the scienti c support and advice of the Center for Sustainable Urban Development / Earth Institute at Columbia University in the City of New York. Considering the time interval in question, some updates were made in certain parts of the analysis. These studies are ai- med to analyze the realities of poverty and exclusion, namely the issues related with homelessness, in the city of Lisbon and using the reality of other countries, particularly USA, as a source of comparison. The book’s main objective is to ad- dress a number of questions from a theoretical approach and from an evaluation perspective on three main topics: Poverty, Welfare State and Social Exclusion/ Homelessness. It was the author’s goal to present a contribution to the analysis of a reality, both complex and dramatic, that Communities at different levels (local, regional, national and international) have to address and change, and to present some insights for a better understanding of the causes and consequences of pathways of life marked by deprivation and poverty.