The Anthropocene deserves spatial as well as temporal analysis. "Patchy Anthropocene" is a conceptual tool for noticing landscape structure, with special attention to what we call "modular simplifications" and "feral proliferations." This introduction suggests guidelines for thinking structurally about more-than-human social relations; "structure" here emerges from phenomenological attunements to specific multispecies histories, rather than being system characteristics. Indeed, we discuss "systems" as thought experiments, that is, imagined holisms that help make sense of structure. Ecological modeling, political economy, and alternative cosmologies are systems experiments that should rub up against each other in learning about the Anthropocene. We address the misleading claim that studies of nonhumans ignore social justice concerns as well as suggesting ways that ethnographers might address "hope" without rose-colored glasses. This introduction offers frames for appreciating the distinguished contributions to this supplement, and it traces key changes in anthropological thinking from the time of this supplement's predecessor, the Wenner-Gren Foundation-sponsored 1956 volume, Man's Role in Changing the Face of the Earth. Rather than interrogating philosophies of the Anthropocene, the supplement shows how anthropologists and allies, including historians, ecologists, and biologists, might best offer a critical description.