New Testament letters are compared with the private, business, and administrative letters of Greco-Roman antiquity and analyzed against this background. More than 8.000 letters - preserved on papyrus, potsherds or tablets from Egypt, Israel, Asia Minor, North Africa, Britain, and Switzerland - have been edited so far. Among them are not only short notes by writers with poor writing skills, but also extensive letters and correspondences from highly educated authors. They testify to the high art of Paul of Tarsus, who knew how to make excellent use of epistolary formulas or enrich them with new variants, but they also show that some New Testament letters clearly fall outside the framework of standard epistolography, raising new questions about their authors and their genre. The introductions and discussions offered in the volume reflect the current state of research but also offer new results. Over 130 papyrus and ostracon letters are newly translated in their entirety.