Today, nostalgia is inescapable, permeating YouTube comment sections and Instagram filters, the exile’s lament and the homebody’s wistfulness, the rhetoric of the right and the left, popular culture and the Museum of Modern Art. In an extraordinary film, Nostalgia de la Luz (2010), director Patricio Guzmán travels to the driest place on earth, the Atacama desert, where the clarity of the atmosphere allows astronomers to gaze skywards in search of the most distant and oldest traces of the universe. Simultaneously, the mummifying desert heat keeps alive the slenderest hopes of groups of Chilean women who gather daily to comb the earth for any traces of their family members, political prisoners who were murdered and buried in mass graves after 1973 by Pinochet’s regime. In nostalgia, the cosmopolitan’s desire to leave the earth and the provincial’s desire to remain attached to it cross like two ships in the night. Prisoners of Loss: An Atlantic History of Nostalgia is a genealogy of the cosmopolitan construction of the provincial’s nostalgia. This history is virtually unknown. Yet by 1800, nostalgia held an exemplary status in late-Enlightenment medicine as the disease of forced migration and was overwhelmingly diagnosed in the ethnic and racial minority populations whose compulsory migrant labor – as slaves, servants, sailors, and soldiers – helped build the empires of the Atlantic world. Over the course of the nineteenth century, military surgeons like Benjamin Rush designed new domains of hygiene and sanitation to prevent soldiers from developing “camp diseases” like nostalgia. The American Civil War saw 5,266 hospitalizations and 74 deaths of white Union soldiers from the disease, and another 334 hospitalizations and 16 deaths of African-American soldiers. In Brazil, Cuba, and Haiti, plantation physicians listed nostalgia as the primary cause in the suicides of newly imported slaves, who were said to kill themselves out of the “insane” belief that their souls would fly home to Africa. In contrast, transatlantic humanitarians like Jesse Torrey and James Montgomery, as well as Romantics like William Wordsworth, called for the protection of minorities in their homes, whom they deemed were unfitted by their emotions to survive the motions of the global economy. The elasticity of nostalgia in nineteenth- and twentieth-century epistemologies of migration only became possible when it became narrateable. My first chapter reconstructs how nostalgia became a “biopolitical narrative form,” a concept that I define as a temporal, but illogical ordering of a series of formally identical causal explanations of disease. Far from eliminating the circularity of older accounts of pathological causation, biopolitical narrative form is organized by it. When medical geographers introduced the concept of environmental “scarcity” to explain why certain native populations were more nostalgia-prone than others, they merely relocated an earlier equivocation over the primary cause of nostalgia – the home or exile – in the relationship between diagnosis and prognosis. In narrativizing nostalgia, they also preserved the Christian morality that patterned earlier explanations like Johannes Hofer’s initial 1688 dissertation, as well as the analogies of resemblence that held these causes together, in particular the analogy of circulation, which connected excessive motion to excessive emotion and an attendant loss of agency. The consequences would be enormous: in this mutually reinforcing vicious cycle, the nostalgic body is read historically as the product of the minority home, which in turn serves to predict the probability of nostalgia in the minority population. What makes nostalgic form so malleable is the fact that it can be rearranged and remoralized in numerous ways without calling into question this fundamental, organizing tautology. Three subsequent chapters and a coda are organized around the translation of nostalgic form into new sites. My second chapter focuses on “confinement.” I argue that the insertion of nostalgia into new institutional sites like the camp, plantation, and ship produced a major shift away from compulsory mobility, which had underwritten the construction of pathological emotion for centuries. What emerged out of these utilitarian sites was a new poetics of compulsory confinement and the new figure of the compulsive subject. The emergence of medical jurisprudence in 1820s America helped ratify a new definition of nostalgia as a disease that henceforth could only be diagnosed in extreme cases where subjects were unable to articulate the object of their body’s desire. The nostalgic is redefined as someone who is triply confined (by home, by exile, and by the body) and cannot say why. My third and fourth chapters consider two opposing aesthetic cures for the compulsive subject of nostalgia. In Henry James’s The Bostonians (1885), characters lack the ability to give voice to the object of their compulsive desires. In a revision of biopolitical form, what makes these characters nostalgic is not the minority’s exposure to the impoverished home’s pathological motions, as in medicine, or to the ethically impoverished global economy’s pathological motions, as in Romanticism and humanitarianism. Rather, James argues that aesthetic impoverishment is responsible for making Americans into nostalgic bodies, buffeted by the motions of history. We witness here the emergence of the familiar opposition between history and nostalgia, as it is only through the narrative staging of a catastrophic historical event of loss that James can imagine a cure for nostalgia. Sarah Orne Jewett’s The Country of the Pointed Firs (1896), by contrast, anticipates the modernist transvaluation of nostalgia, as it does not seek to negate nostalgic desire through failure, but to use it for therapeutic ends. In remoralizing the ethnic home as a space of refuge, nostalgic narrative does not hinge on a rational solution for the compulsive refusal of loss that sets nostalgia in motion, as in James, but rather on an unlearning of acquisitive desire through an education of the senses, one that is now based on the emulation of the ethnic’s motions and emotions. Prisoners is a genealogy in the strong sense in which Michel Foucault practiced this method, as it unites the genealogy of causality with the genealogy of morality. The case of nostalgia demonstrates the full power of this method. What this study is not is another arch-critical exhortation to avoid nostalgia by seeing it for what it is – a naïve, myopic, self-centered, self-deluding, affective attachment to a lost home. The problem with these critiques is that they implicitly endorse the historian as the ideal embodiment of the Enlightenment human, as the universal figure whose capacities for reason and action are predicated on calming the passions and maintaining a measure of distance from worldly attachments. This is the figure that has historically been used to determine who gets into that exclusive club called cosmopolitanism, that highly regarded travel agency that tells the privileged that they and they alone possess the freedom to move, to leave the world by leaving their emotional baggage behind. When we endorse the historian over the nostalgic, we perpetuate the same medical framework that was used to invent minority populations as people who were uniquely imperiled by travel because their love for home was too great. We perpetuate a framework where the historian is someone who is unmoved by loss, the nostalgic someone who is moved too much. While one detaches and flourishes, the other attaches and withers. This study ultimately calls for a reconsideration of the potential of the moving attachment that we call nostalgia. Most of all, it seeks to know what would happen if nostalgics were allowed to travel lightly.