Arne Naess was born in Slemdal, Norway, in 1912. After earning his Ph.D. at the age of 27, he became the University of Oslo's youngest professor, and Norway's only Professor of Philosophy. Naess was a keen mountaineer, environmentalist and social activist. In 1938, he finished building an isolated wooden hut high in the Hallingskarvet mountains, where he would spend a quarter of his life. It was here that he developed his concept of 'deep ecology,' and his lifelong commitment to the environmental movement. His activity within the movement ranged from grassroots protest, to candidacy for political office with the Green Party, to a post as the first chairman of Greenpeace Norway in 1988. His achievements as a philosopher, ecologist and activist were widely recognised during his lifetime. In 2005 he was knighted and made a Commander with Star of the Royal Norwegian order of St. Olav First Class. He died in Oslo in 2009.