Galtung is known for contributions to sociology in the 1950s, political science in the 1960s, economics and history in the 1970s, macrohistory, anthropology, and theology in the 1980s. He has developed several influential theories, such as the distinction between positive and negative peace, structural violence, theories on conflict and conflict resolution, the concept of peacebuilding,[3] the structural theory of imperialism, and the theory of the United States as simultaneously a republic and an empire.[4] He has often been critical of western countries in their attitude to the Global South. Galtung has been a major intellectual figure of the New Left since the 1950s.[5] He was awarded the Right Livelihood Award in 1987 and has received many other prizes and accolades.