[1][2] Hamilton became known for his theoretical work expounding a rigorous genetic basis for the existence of altruism, an insight that was a key part of the development of the gene-centered view of evolution.

He became interested in natural history at an early age and spent his spare time collecting butterflies and other insects.

As a 12-year-old, he was seriously injured while playing with explosives his father had that were left over from making hand grenades for the Home Guard during World War II.

Hamilton had to have a thoracotomy and parts of fingers on his right hand had to be amputated in King's College Hospital to save his life.

Hamilton enrolled in an MSc course in demography at the London School of Economics (LSE), under Norman Carrier, who helped secure grants for his studies.

Later, when his work became more mathematical and genetical, he had his supervision transferred to John Hajnal of the LSE and Cedric Smith of University College London (UCL).

Haldane had seen a problem in how organisms could increase the fitness of their own genes by aiding their close relatives, but not recognised its significance or properly formulated it.

Hamilton worked through several examples, and eventually realised that the number that kept falling out of his calculations was Sewall Wright's coefficient of relationship.

Much of the discussion relates to the evolution of eusociality in insects of the order Hymenoptera (ants, bees and wasps) based on their unusual haplodiploid sex-determination system.

The supergenes notion (sometimes called the Green-beard effect) - that organisms may evolve genes that are able to identify identical copies in others and preferentially direct social behaviours towards them - was theoretically clarified by Hamilton in 1987.

[5] In his 1970 paper Selfish and Spiteful Behaviour in an Evolutionary Model Hamilton considers the question of whether harm inflicted upon an organism must inevitably be a byproduct of adaptations for survival.

Between 1964 and 1977, Hamilton was a lecturer at Imperial College London (including Silwood Park, where a building is named in his honour).

Hamilton combined his extensive knowledge of natural history with deep insight into the problem, opening up a whole new area of research.

This shortcoming would not affect the recognition of his work, however, as it was popularised by Richard Dawkins in the book The Selfish Gene published in 1976.

Likewise, parasites were able to evolve mechanisms to get around the organism's new set of genes, thus perpetuating an endless race.

[11] During the 1990s, Hamilton became interested in the now-discredited hypothesis that the origin of HIV lay in Hilary Koprowski's oral polio vaccine trials in Africa during the 1950s.

To look for evidence of the hypothesis, Hamilton went on a 2000 field trip to the Democratic Republic of the Congo to assess natural levels of simian immunodeficiency virus in primates.

[16] A secular memorial service (he was an agnostic[17]) was held at the chapel of New College, Oxford on 1 July 2000, organised by Richard Dawkins.

He, however, had written an essay on My intended burial and why in which he wrote:[18] I will leave a sum in my last will for my body to be carried to Brazil and to these forests.

[citation needed] From 1994, Hamilton found companionship with Maria Luisa Bozzi, an Italian science journalist and author.