My thesis explores the links between communality, the metabolic relationship, and ecological sustainability. It does so through case study research of a rundale system of production context (because rundale was a communal mode of production) in North-West Mayo in Ireland (c. 1930s-50s). The aim of my research is to contribute to discussion about the relationship between society and nature tied to agriculture. I investigate a pre-capitalist setting that was marginal in terms of rundale existing at the margins of capitalism. But crucially, the setting was ecologically marginal with the productiveness of agriculture being extremely limited by location and the harsh physical environment that existed there. This double marginality made it possible to reveal certain things: On the one hand, it highlighted the social processes involved in enabling the society to engage with capitalism without becoming capitalist, and in so doing emphasised the significance of communal relations of production in helping to safeguard sustainable agricultural production in the area; on the other hand, because of the extreme physical environment concerned it was possible to unpack the social processes involved in dealing with nature’s forces as they confronted society there, because in having to produce under such extreme conditions the social processes involved in safeguarding production were more exposed. I highlight the people’s ingenuity in appropriating nature’s forces to allow them to successfully produce within a socio-ecological relationship where both nature and society acted as causal variable at different times within their interaction. I demonstrate this through a focus on processes occurring in social and natural systems and sub-systems. I explore social, ecological, and socio-ecological relationships as they acted to affect the metabolic relationship and ecological sustainability. I use an emergent primarily qualitative mixed method case study research approach to uncover nuanced data on the phenomena of interest and to allow the data to shape the research process to a large degree. I apply an iterative analysis process to allow new avenues of inquiry as they emerge from the research process to be followed up. The result is an unfolding research process. My work is also presented in an unfolding cyclical manner with separate sections offering different levels of analysis, and with each of those sections each offering two types of analysis – one informed by scholarly insight and the other informed by empirical data. The results of each system level analysis section provide the impetus for which system level is discussed next until all systems have been discussed. The key finding of my research is that communality supported agricultural sustainability within the setting investigated