James M. Buchanan was an American economist known for his work in public choice theory, which examines how political decisions are made and how they can be influenced by self-interest. He was awarded the Nobel Prize in Economic Sciences in 1986 for his contributions to the understanding of the relationship between economics and political science. Buchanan co-founded the Virginia School of Political Economy, emphasizing the importance of individual choice and the role of institutions in shaping economic outcomes. His ideas have had a significant impact on economic policy and the study of government behavior, influencing both economists and political scientists.