History of anthropological theory, in which he was the first writer to discuss the topic in terms of long-standing philosophical and epistemological conflicts. Previously, the convention had been to write as though the field developed simply as an accumulation of “discoveries.” Leaf described the conflict as between monism and dualism, with the former represented in modern philosophy and epistemology by Skepticism and Pragmatism, and the latter by the various forms of idealism and materialism--including positivism and Marxism. Although subsequent writers have emphasized different issues, explicit discussion of philosophical and epistemological assumptions has now become common. He was also the first modern writer to call attention to the roots of anthropological theory in legal theory.
General social theory, in which in the post-war period he was the second writer, after Fred Bailey, to explicitly repudiate the conception that the task of social analysis was to show the underlying unity of society or social structure. Leaf has argued consistently for organizational pluralism. In the sphere of culture, he has similarly argued that no community ever has a single unified system of ideas and values or “symbols and meanings,” at any level. There are always multiple, independent and often mutually opposed, cultural idea-systems. With Dwight Read, Michael Fischer, Douglas R. White, and others he has contributed to the development of methods for eliciting and describing such systems with previously unattained clarity and verifiability. These include the ideas that define kinship, religion, government, local organizations, and productive organizations. The theoretical effort includes developing a more general statement of Shannon and Weaver’s A Mathematical Theory of Communication.
In development studies, he has been among a group of development specialists primarily drawn from anthropology, geography, and sociology, who have argued for the orientation that Michael Cernea and Robert Chambers have described s “putting people first.” Others have described it under the heading of promoting “people’s participation” in project design and management. The orientation rejects both dirigiste central planning and laissez-faireneo-liberalism, with their respective theoretical justifications.
1992 "Irrigation and Authority in Rajasthan" Ethnology.
2003 “Ethnography and Pragmatism” in Alfonso Morales, ed. Renascent Pragmatism.
2003 “Pragmatic Legal Norms” in Alfonso Morales, ed. Renascent Pragmatism.
2004 “What is “Formal” Analysis?” In Cybernetics and Systems: An International Journal
2005 “The Message is the Medium: Language, Culture and Informatics” In Cybernetics and Systems: An International Journal.
2005 “Romanticism, Meaning, and Science” in Language, Culture and the Individual: A Tribute to Paul Friedrich. Catherine O’neil, Mary Scoggin, and Kevin Tuite, eds.