According to the tenets of evolutionary biology, altruistic behaviour - self-sacrifice for the sake of the greater good - should be an anomaly. Nevertheless, scientists observe altruistic behaviour in virtually every species. The existence of altruism has intrigued and confounded scientists and philosophers for generations and in The Altruism Code, Oren Harman chronicles humanity's many attempts to come to terms with this rich and paradoxical phenomenon. The central character in this quest is George Price, a tortured genius of 20th century evolutionary biology who devoted much of his career to understanding the scientific basis for altruistic behaviour. As the story of Price's life and career unfurls, Harman weaves in other narrative threads that illustrate the nearly universal existence of altruism: from stage-spitting tadpoles and 'free-riding' cuckoo birds to self-sacrificing slime-molds and naked blind mole rats, spanning the globe from the Siberian tundra to the South American tropics. It is against this biological quest that the story of George Price's troubled life unfolds. Born in New York in 1922, he eventually left America for London in 1967. He arrived in London with virtually nothing - his family was broken; he had switched countless jobs and was unemployed; he hardly spoke to his brother and barely knew his daughters; and his mother was writing herself letters from his dead father.

He was forty-five years old and had utterly failed to make his mark on the world. Once in London, however, he started to work with W.D. Hamilton and John Maynard Smith. He devised what is now called the Price Equation - widely held to be the best mathematical, biological and evolutionary representation of altruism. Price went on to experience what he called a 'coincidence conversion' and converted to Christianity after being a staunch atheist for most of his life. With this conversion came his quest to obtain true selflessness. He dedicated his life to helping the homeless and destitute in London.

He gave up all his worldly possessions and ended up living in poverty himself. Emaciated, ill and destitute, he finally killed himself in 1975 - the burden of being destitute and unable to help the homeless too much for him to bear.