This article examines the forms of intergenerational kinship and care work that Black men perform within and beyond US prisons. First, I offer a historical conceptualization of domestic warfare as a multilayered process that targets Black radical activism, social/familial life, and the interiority of Black subjectivity. I argue that the rupturing of intimacy and familial relationships precipitated by the prison should be understood not as an incidental byproduct of a poorly designed carceral regime but as a tactic of war and a condition of genocide. Next, I theorize letter writing as an ethnographic and political modality that is part of a broader repertoire of strategies that Black men deploy to survive within and rebel against domestic war. I then draw on correspondence between myself and Absolute, an imprisoned Black man, as well as oral histories I collected with elders of New York's radical prison movement, to show how Black men care for each other, forge kinship networks, and transmit knowledge. I close by showing how Absolute carries on traditions of knowledge production and care to younger generations of captive Black men and by connecting this intergenerational practice to forms of collective rebellion. [prisons, kinship, Black masculinity, letters, warfare] RESUMEN Este artículo examina las formas de parentesco intergeneracional y el trabajo de cuidar que hombres negros desempeñan dentro y más allá de las prisiones de Estados Unidos. Primero, ofrezco una conceptualización histórica de la guerra doméstica como un proceso de múltiples niveles que va dirigido al activismo radical negro, vida