1. Darwin, C. The Origin of Species Ch. VIII (The Modern Library, 1859/, 1958)Although Darwin did not confront the problem of altruistic behaviour directly, he was aware of the challenge posed by the development of sterile castes in some social insects and, in Chapter VIII of The Origin of Species , he describes how he thought, at first, that this was fatal to the whole theory of natural selection.
2. Kropotkin, P. Mutual Aid (William Heineman, 1908)
3. Wynne-Edwards, V. C. Animal Dispersion in Relation to Social Behaviour (Oliver and Boyd, 1962)
4. Hamilton, W. D. The genetical evolution of social behaviour. I. II. J. Theor. Biol. 7, 1–52 (1964)Although they are usually cited as an explanation of the role of kin selection in maintaining cooperative behaviour, Hamilton’s papers and Hamilton’s Rule (see Box 1) also provide the basis for explaining cooperation between non-kin.
5. Axelrod, R. The Evolution of Cooperation (Basic Books, 1984)