Abstract This essay introduces the major themes and concerns of “Genealogies of Black Modernity in the Long Nineteenth Century,” a special issue of American Literary History. How does modernity look when read through Black diasporic literary production in the long nineteenth century, broadly conceived? What new narratives can we create by reading this literature as participating in and producing transatlantic genealogies of literary modernity? How does reading Black literary modernity in the nineteenth century disrupt our understandings of modernity as a conceptual framework both for contemporary scholarship and as an object of nineteenth-century Black intellectual inquiry? This introductory essay defines Black modernities of the long nineteenth century as a set of related, sometimes connected, practices and questions focused on the nature of Black life and culture in an ever-shifting antiblack world. Writers from Phillis Wheatley to Pauline Hopkins—to offer one framing—were invested in chronicling and intervening in the newness of their moment, even as they worked to imagine new possibilities for the future. Our task, then, was to deliberate over what something called modernity meant and means for and in African American literary history through the archive of Black writing and through the terms and forms these writers set forth.