The numbers of individuals who can be classified as being homeless are, not surprisingly, affected by a variety of reasons which include economic factors such as poverty and unemployment, which may or may not be a result of rapid urbanization in many countries. There is considerable research evidence indicating that rates of psychiatric disorders are higher in homeless individuals, although, in some cases, psychiatric illness itself may lead to homelessness if no safety net is available. Homelessness and psychiatric disorders are both strongly affected by various social determinants and thus may feed into each other. Keeping these issues across the globe in mind, this volume aims to provide up-to-date research and policy evidence from across different countries and cultures. The bi-directional relationship between homelessness and mental ill health is still far from being completely understood, but the impact of social and psychological factors is of interest. Also, the result of transgenerational factors on people’s mental health is worth exploring. This volume aims to provide a cultural and international overview with contributors and editors from across various continents.