Known chiefly for his theory of ethnicity, Fredrik Barth has made several important contributions to anthropology. Beginning as a political anthropologist concerned with the relationship between individual strategies and social form, he reformulated segmentary lineage theory following fieldwork in Swat. He later wrote about ecological adaptations among nomads in Persia and developed a transactional model of social life inspired by the theory of games, before shifting, around 1970, to the study of cosmologies and knowledge systems, mainly based on fieldwork in New Guinea and Bali. A very prolific fieldworker, Barth has also published monographs from Kurdistan and Oman. He represents a processual view of social life, emphasizing events and interaction rather than structural and historical features of society. As a professor at the University of Bergen from 1961 to 1973, he was the major influence on the development of modern Norwegian social anthropology.