In this volume, Paul Robertson re-describes the form of the apostle Paul's letters in a manner that facilitates transparent, empirical comparison with texts not typically treated by biblical scholars. Paul's letters are best described by a set of literary characteristics shared by certain Greco-Roman texts, particularly those of Epictetus and Philodemus. Paul Robertson theorizes a new taxonomy of Greco-Roman literature that groups Paul's letters together with certain Greco-Roman, ethical-philosophical texts written at a roughly contemporary time in the ancient Mediterranean. This particular grouping, termed a socio-literary sphere, is defined by the shared form, content, and social purpose of its constituent texts, as well as certain general similarities between their texts' authors.