Taking design as a geographical agent implicated in the territorial engravings of contemporary urbanization, this issue of New Geographies embraces the planetary as the spatiotemporal stage on which more-than-human geographies and territorial formations are currently being produced and contested. Its contributions traverse an array of manufactured environments—technological domains, infrastructural networks, underground spaces, operational landscapes, and extraterrestrial extensions—read as “third natures” where human and nonhuman agencies are materially composed within the hybrid spatialities of twenty-first-century urbanization. Organized as a loose constellation of critique, speculation, dialogue, and narrative, the volume proposes a diagnostic cartography of the cultural, biopolitical, and sociotechnical conditions through which a novel posthuman spatial condition is emerging—and through which the urban itself is being reconfigured.