The kin selection revolution started in a pub in the mid 1950s. Biologist J. B. S. Haldane was asked if he would give his life to save his brother. A few scribbled calculations later, he provocatively replied that he would only die for at least two brothers, or eight cousins.  Why? Because a gene coding for such altruism can only survive if it leaves enough copies of itself in relatives. Human siblings share on average half of their genes, and cousins one-eighth. Hence, two siblings, or eight cousins equal one self. The concept was published by Haldane in 1955, but was generalised and mathematically formalised by William Hamilton in 1964.  The revolution ignited. Group selection mechanisms, proposed in particular by Vero Wynne-Edwards, no longer appeared to explain altruism. The individual came to be seen as the protagonist of natural selection. Soon the gene took its place. Bodies could be regarded as merely the genes' way of making more genes, as famously expressed in 1976 by Richard Dawkins's metaphor of the selfish gene. In two ground-breaking books, The Insect Societies (1971) and Sociobiology (1975), Edward O. Wilson launched a new research programme that promised to explain the social behaviour of all animals under a single unifying theory, with kin selection at its core. Sociobiologists faced accusations of racism and sexism, because of their then-radical views on human nature. Scientists such as Stephen Jay Gould entered the fray, arguing that there was more to evolution and social behaviour than genes maximising their own fitness. Today, the majority of behavioural ecologists, knowingly or not, follow the gene-centred sociobiological approach. Wilson, however, has now changed flag, turning against what he helped create.