The title of this book suggests that the main disciplinary divide in research on ‘CPRs’ is between economists and anthropologists. But the acronym is itself open to two alternative expansions, viz., Common Property Resources and Common Pool Resources, that highlight the social and the biophysical dimension of the problem respectively (Stevenson, 1991). The starting point of this paper, therefore, is that interdisciplinarity in the context of CPRs has to be (at least) a three way conversation between economists, anthropologists and natural scientists.2 Implicit in this point of departure is also the idea that having this conversation and eventually a collaboration of some kind is desirable3 and to some extent possible. The question therefore is not “whether” but “how”. Answering this question requires a comprehensive understanding of the different barriers that prevent this three-way conversation from being a productive one. I believe that the barriers include not just differences in epistemology and method that have been well-debated in other chapters of this book and elsewhere, but differences of other kinds as well. I suggest a four dimensional categorisation of these barriers, and then discuss the form and relative importance of each in the different sides of the conversational triangle using various illustrations. Finally, I suggest a few practical ways of overcoming these barriers. These discussions, illustrations and suggestions draw as much upon my personal experience in crossing disciplinary boundaries and conducting interdisciplinary research on forests, watersheds and forest-watershed linkages as upon the examples available in the CPR or broader environmental studies literature.