Through lively, engaging narrative, Understories demonstrates how volatile politics of race, class, and nation animate the notoriously violent struggles over forests in the southwestern United States. Rather than reproduce traditional understandings of nature and environment, Jake Kosek shifts the focus toward material and symbolic “natures,” seemingly unchangeable essences central to formations of race, class, and nation that are being remade not just through conflicts over resources but also through everyday practices by Chicano activists, white environmentalists, and state officials as well as nuclear scientists, heroin addicts, and health workers. Drawing on two years of ethnographic fieldwork and extensive archival research, he shows how these contentious natures are integral both to environmental politics and the formation of racialized citizens, politicized landscapes, and modern regimes of rule. Kosek traces the histories of forest extraction and labor exploitation in northern New Mexico, where Hispano residents have forged passionate attachments to place. He describes how their sentiments of dispossession emerged through land tenure systems and federal management programs that remade forest landscapes as exclusionary sites of national and racial purity. Fusing fine-grained ethnography with insights gleaned from cultural studies and science studies, Kosek shows how the nationally beloved Smokey the Bear became a symbol of white racist colonialism for many Hispanos in the region, while Los Alamos National Laboratory, at once revered and reviled, remade regional ecologies and economies. Understories offers an innovative vision of environmental politics, one that challenges scholars as well as activists to radically rework their understandings of relations between nature, justice, and identity.