AbstractThe 1622 publication of Imprisonment of Mens Bodies for Debt marked the beginning of a decades-long tradition of anti-carceral activism in London's prisons. By recovering prison activists’ practices of publication and republication, the article reveals a vibrant world of textual production in prisons that enabled political interventions grounded in the material and structural conditions of incarceration. Anti-carceral activism relied on the varied uses of print and manuscript that formed part of the day-to-day experience of incarceration. These local practices were combined with new processes of national political communication, from parliamentary petitioning and news printing in the 1620s, to manuscript pamphleteering and the demand for legal texts in the 1630s, and the explosion of radical printing and political agitation in the 1640s. Operating at the intersection of quotidian textual practice and developing forms of political communication, prison activism became engaged in wider currents of national debate. Thus, the article demonstrates how a relatively marginal social constituency could utilize these modes and networks of political communication across multiple media and how, in turn, such groups could both develop connections to radical political networks and come to imagine their cause as part of a wider political moment.