This forum opens a conversation between the history of technology and the history of capitalism by considering the "paper technologies of capitalism" of the seventeenth, eighteenth, and nineteenth centuries in England and the United States. Seth Rockman offers an overview, connecting a recent exhibition of quotidian business ephemera to scholarly efforts to historicize the economic past, to engage material artifacts as things, and to embed the production of social knowledge in communities of practice. Three essays follow: William Deringer considers the "computational technologies" available in England to calculate future values; Caitlin Rosenthal traces the "rule of three" in the everyday transactions of the "innumerate" in the U.S. Early Republic; Jonathan Senchyne examines the materiality of paper within the emerging "rags to riches" tropes of nineteenth-century capitalist culture. Finally, Barbara Hahn concludes the forum with reflections of the overlapping terrain of the history of technology and the history of capitalism.