Part I. Population Genetics and Evolution Theory: 1. Population genetics R. C. Lewontin; 2. Somatic mutations as an evolutionary force M. Slatkin; 3. The flow of genes through a genetic barrier B. O. Bengtsson; 4. Intraspecific resource competition as a cause of sympatric speciation J. Seger; 5. Darwinian evolution in ecosystems: the Red Queen view N. C. Stenseth; 6. Game theory and animal behaviour G. A. Parker and P. Hammerstein; 7. Behavioural structure and the evolution of cooperation R. E. Michod and M. J. Sanderson; Part II. Adaptations, Constraints and Patterns of Evolution: 8. Evolutionary ecology and John Maynard Smith R. M. May; 9. The evolution of senescence M. R. Rose; 10. Germination strategies J. A. Leon; 11. When plants play the field J. Silvertown; 12. Homage to the null weasel P. H. Harvey and K. Ralls; 13. Asymmetric contests in social mammals: respect, manipulation and age-specific aspects C. Packer and A. Pusey; 14. Functions of communal care in mammals J. L. Gittleman; Part III. the Evolutionary Ecology of Sex: 15. Recombination and sex: is Maynard Smith necessary? J. Felsenstein; 16. Birth sex ratios and the reproductive success of sons and daughters T. H. Clutton-Brock; 17. Distribution of dioecy and self-incompatibility in angiosperms D. Charlesworth; 18. Natural selection and the evolutionary ecology of sex allocation E. L. Charnov; 19. The evolution of sexual size dimorphism in birds and mammals: a 'hot-blooded' hypothesis P. J. Greenwood and P. Wheeler; 20. Leks and the unanimity of female choice J. W. Bradbury, S. L. Vehrencamp and R. Gibson.