1. Mountain gorillas of the Virungas: a short history Kelly J. Stewart, Pascale Sicotte and Martha M. Robbins; Part I. Variation in the Social System of Gorillas: 2. Variation in the social system of mountain gorillas: the male perspective Martha M. Robbins; 3. Female mate choice in mountain gorillas Pascale Sicotte; 4. Dispersal patterns, group structure and reproductive parameters of eastern lowland gorillas at Kahuzi in the absence of infanticide Juichi Yamagiwa and Alastair McNeilage; Part II. Within-group Social Behaviour: 6. Development of infant independence from the mother in wild mountain gorillas Alison Fletcher; 7. The social relationships of immature gorillas and silverbacks Kelly J. Stewart; 8. Social relationships of female mountain gorillas David P. Watts; 9. Vocal relationships of wild mountain gorillas A. H. Harcourt and Kelly J. Stewart; Part III. Feeding Behaviour: 10. Diet and habitat use of two mountain gorilla groups in contrasting habitats in the Virungas Alastair McNeilage; 11. Clever hands: the food processing skills of mountain gorillas Richard W. Byre; Part IV. Conservation and Management of Mountain Gorillas: 12. Assessment of reproduction and stress through hormone analysis in gorillas Nancy Czekala and Martha M. Robbins; 13. Clinical medicine, preventive health care and research on mountain gorillas in the Virunga volcano region Anthony B. Mudakikwa, Michael R. Cranfield, Jonathon M. Sleeman and Ute Eilenberger; 14. Conservation oriented research in the Virunga region Andrew J. Plumptre and Elizabeth A. Williamson; 15. Status of the Virunga mountain gorilla population H. Dieter Steklis and Netzin Gerald-Steklis; Afterward: Mountain gorillas at the turn of the century Bill Weber and Amy Vedder.