Anthropology of the Machine: Tokyo’s Commuter Train Network is an exploration of collective life formed at the interstices of human and machine operation within one of the most complex and large-scale technical infrastructures in the world. Adopting a simultaneous critical and optimistic approach, it is an attempt to think with the specific quality of relations formed within Tokyo’s commuter rail infrastructure in order to develop a mode of analysis adequate to the technological complexity of contemporary society and to explore emergent ontologies of human and machine co-constitution. In so doing, it draws attention not only to Tokyo’s commuter train network’s infamously packed trains and precision schedule but more importantly its operation at the extreme edge of sustainability beyond its structural capacity. Such a system, it posits, embodies the contradictory and unsustainable logic defining our contemporary relationship with technology. At the same time, through a theoretically novel approach that emphasizes the generative gaps within the network’s immersive mediation, Anthropology of the Machine advances Tokyo’s commuter train network as a unique setting through which to question received discourses on technology and to re-conceptualize the human relationship with machines toward a more sustainable future.