This detailed book aims at defining and reassessing the role of population genetics in conservation biology, and tries to identify progress made in the field during the last decade. It deals with the subject of conservation genetics from several different currently researched points of view, namely: ecological and demographic measures of rarity or population persistence; loss of genetic variation; inbreeding; reduced migration rates and increased selective pressures under stress; and the role of social behaviour and metapopulation structure. Several case studies and scenarios are used to illustrate the application of genetic information in conservation practices.