The introduction argues for the advancement of anthropological theory through engagement with the work of Michel Serres. Particularly striking is the potentiality of porosity as a conceptual pivot to explore both Serres and ethnographic subjects. Touring Serres’s key works on time, religion, parasites, and ecology, the chapter argues that the porous becomings of interlocutors are best considered within the topological nexus of human–planetary concerns that Serres so skillfully navigates. Serres facilitates this scaling of individual and global, mundane and sublime, past and future through concepts such as background noise, bifurcation, contracts and percolators, and more-than-human messengers. Porosity here stands for communication between the disciplines, a transcendence of (beyond-)human realms, and journeys through horizons of space and time that connect often abstract theorizations with the grassroots realities of ethnographic knowledge.