Sentient Atmospheres argues that the sense of atmosphere shifts from descriptive medium to narrative agent in twentieth and twenty-first century American literature. For writers such as Henry James, Michael Herr, Ursula Le Guin, David Foster Wallace, and Colson Whitehead, atmosphere no longer functions as a scenic backdrop for human action or a screen for the projection of human emotion. Rather, atmosphere irrupts into the human lifeworld as a narrative actant, whether as rival, antagonist, paramour or partner. Collectively, these writers reimagine the relation between subject and atmosphere, registering and reframing salient moments in the modern history of atmospheric modification, from the environmental effects of world war, through the toxic ecologies of late capitalist consumer culture, to our current crisis of anthropogenic climate change. Sentient Atmospheres reveals how American authors have elaborated atmosphere into an autonomous entity, always in dialectical interplay with human history, but operating in the human world with its own agential thrust.