Sustainable management of the world's livestock genetic diversity is of vital importance to agriculture, food production, rural development and the environment. "The State of the World's Animal Genetic Resources for Food and Agriculture" is the first global assessment of these resources. Drawing on 169 Country Reports, contributions from a number of international organizations and 12 specially commissioned thematic studies, it presents an analysis of the state of agricultural biodiversity in the livestock sector - origins and development, uses and values, distribution and exchange, risk status and threats - and of capacity to manage these resources - institutions, policies and legal frameworks, structured breeding activities and conservation programmes. Needs and challenges are assessed in the context of the forces driving change in livestock production systems. Tools and methods to enhance the use and development of animal genetic resources are explored in sections on the state of the art in characterization, genetic improvement, economic evaluation and conservation. The main findings of the report are summarized in "The State of the World's Animal Genetic Resources for Food and Agriculture - in brief", of which the Arabic, Chinese, English, French, Russian and Spanish versions can be found on the attached CD-ROM and are also available separately in printed form. As well providing a technical reference document, the country-based preparation of "The State of the World" has led to a process of policy development and a "Global Plan of Action for Animal Genetic Resources", which once adopted, will provide an agenda for action by the international community.