The purpose of this article is to analyze the interdisciplinary cooperation and interaction between American legal realists and anthropologists during the interwar period. Using scholarly publications and manuscripts as its sources, it argues that despite the lack of recognition in earlier studies, there were transfers of important methodological and substantive influences that were crucial to the creation of legal anthropology as it is known today, as well as the whole field of law and society studies. Writers of the era like Karl N. Llewellyn, E. Adamson Hoebel, Felix S. Cohen, Franz Boas, and Bronislaw Malinowski utilized interdisciplinary influences to criticize scholarly formalism as well as social and political conservatism, seeking to replace conceptual structures with scientific facts gained from studies.