Revealed and exacerbated by the shift from a system of oral exchange to a system of written exchange, the issue of illiteracy in prison raises questions about prisoners’ relation to knowledge. On the basis of a qualitative survey of 40 illiterate inmates and a dozen or so professionals, this paper discusses the modifications to experience and the reconstruction of identity in prison. The results show how incarceration upsets the ordinary experience of the oral exchange and how identity is reconstructed through training.