Disciplining Christians reconsiders several of Augustine's most well-known letter exchanges, including his famously controversial correspondence with Jerome and his efforts to engage his Donatist rivals in a letter exchange. It reads these letters with close attention to conventional epistolary norms and practices, in an effort to identify innovative features of Augustine's epistolary practice. In particular, it notes and analyzes Augustine's adaptation of the traditionally friendly letter exchange to the correction of perceived error in the Christian community. In transforming the practice of letter exchange into a tool of correction, Augustine draws on both the classical philosophical tradition and also scripture. His particular innovation is his insistence that this process of correction can-and often must-be done in the potentially public form of a letter exchange rather than in the privacy of a face-to-face conversation. This is particularly true when the perceived error is one that has the potential to jeopardize the salvation of the entire Christian community. In offering epistolary correction, and requesting reciprocal correction from his correspondents, Augustine treats his practice of letter exchange as a performance of Christian caritas. Indeed, in his view, the friendliest correspondence was that which was concerned solely with preserving the salvation of the participants. In recognizing Augustine's commitment to the corrective correspondence and thus reading his letters with attention to their corrective function, we gain new insights into the complicated dynamics of Augustine's relationships with Jerome, Paulinus of Nola, the Donatists, and Pelagius.