Often assumed to be simply the opposite or absence of life, death is in truth a distinctively uncertain category which troubles assumptions about what it means to be alive, and what it means to be human. In this project, I explore what happens to understandings of bodily endings when the "normal human" is de-centered from the concept of death. I take a post-Enlightenment, post-humanist approach in the mode espoused by Rosi Braidotti (2006, 2019) which seeks to move beyond the elite and exclusive category of "human," as well as to get outside of anthropocentric patterns of thought. This project focuses on shifting definitions and meanings of death in the midst of advanced life-sustaining technologies and against a backdrop of cultural fascination with immortality as represented by the modern intensive care unit. Employing ethnographic methods and concepts from feminist new materialism, and founded on an in-depth understanding of posthuman theory, this work contributes novel analyses of how death happens in technological spaces, and how our understandings of it could be approached differently. I contrast cases of patients sustained on life-support technologies seemingly beyond their desired limits with those of individuals declared to be dead against their beliefs to explore ontological, epistemological, and practical elements presently maintaining the appearance of universal definitions of death. A final analysis of media cases of people who continue to produce life through pregnancy despite being categorized as dead helps to reconfigure assumptions about life, death, and life sustaining technologies into a new understanding of how bodily endings, alongside perceptions of liveliness, are always a particular product of ongoing and unfolding social and technical iii | relations. Ultimately, I suggest that life sustaining technologies and their capacity to promote impressions of vitality allow us to better appreciate how death is already always a part of life, a perhaps unwanted "other" that we might learn to tolerate and accept, a personal ethical threshold of existence with the potential to transport us into different futures. This work expands the application of posthuman theory into the domain of clinical death and demonstrates the added value of posthuman analyses in medical spaces. iv | ACKNOWLEDGEMENTS This dissertation was made possible through the intellectual contributions, commitment of time and energy, and emotional care of many, many people. I am also grateful to organizations such as the Canadian Social Science and Humanities Research Council, the Ontario Graduate Scholarship, Carleton University, and the Department of Sociology and Anthropology for making this work and this degree possible through grants and scholarship funding.A huge thank you is owed to my supportive and engaged committee, who have truly helped to guide the direction and improve the focus of this project. To my supervisor, Carlos Novas, thank you for inspiring me to pursue inquiry in the field of STS and posthumanism, and for our ma...