Central to this article is an Arabic letter written on papyrus in an Egyptian prison in the late ninth or early tenth century ce. The author complains that he and his companions are being kept in terrible conditions and that they have received insufficient support from outside prison. Interestingly, he indicates that there is a strong inclination among the group to offer themselves as slaves in order to find relief from their crushing living conditions. By doing so, they would have transgressed Islamic law of that time, which forbade the enslavement of free inhabitants of the Realm of Islam. The letter is a unique source for the social history of slavery, especially self-enslavement, in Abbasid society. This article presents, translates, and annotates this letter and offers a detailed study of its contents.