This dissertation examines the ways in which slave owners sought to depict and manage the inner life of the enslaved in the two most lucrative coffee- and sugar-producing regions of the nineteenth-century Atlantic world. Through a comparative analysis of medical, literary, and anthropological texts, this study shows that feeling, on the one hand, informed theories and practices of slave management as much as it inspired sentimental accounts of the institution of slavery. Captives, on the other hand, were not mere objects of a white imagination. In poetry and in autobiographical writings, enslaved and formerly enslaved authors made their own incursions into the culture of feeling that permeated nineteenth-century Cuban and Brazilian societies. In so doing, they articulated conceptions of bondage and emancipation that challenged the affective registers and epistemological regimes of their times. The six chapters of this dissertation trace a century-long genealogy of writings concerned with the affective lives of enslaved and free people of African descent—from the expansion of the slave trade in the late-eighteenth century through the emergence of reformist and abolitionist rhetoric in the mid-nineteenth century to the aftermath of emancipation in Cuba (1886) and Brazil (1888). Drawing from studies on the relationship between the Church, the law, and mercantilism in the early modern Iberian empires as well as from works on sentimentalism in nineteenth-century Cuba, this dissertation investigates the ways in which religious discourses developed into a particular rhetoric of feeling and affect that was central to the emerging Brazilian and Cuban bourgeoisies from the late eighteenth century onwards.