This volume uses recent research from the World Bank to document and analyze the bidirectional relationship between poverty and migration in developing countries. The case studies chapters compiled in this book (from Tanzania, Nepal, Albania and Nicaragua), as well as the last, policy-oriented chapter - illustrate the diversity of migration experience and tackle the complicated nexus between migration and poverty reduction. Two main messages emerge: Although evidence indicates that migration reduces poverty, it also shows that migration opportunities of the poor differ from that of the rest. In general, the evidence suggests that the poor either migrate less or migrate to low return destinations. As a consequence, many developing countries are not maximizing the poverty-reducing potential of migration. The main reason behind this outcome is difficulties in access to remunerative migration opportunities and the high costs associated with migrating. It is shown, for example, that reducing migration costs makes migration more pro-poor. The volume shows that developing countries' governments are not without means to improve this situation. Several of the country examples offer a few policy recommendations towards this end.