While some letters from Merovingian-era Gaul are well known—for example, Remigius’s letters to Clovis or Radegund’s letters founding her monastery—the scale and scope of extant and attested letters tell us more about the period than the sum of data from individual documents. The cumulative range of known epistolary communications indicates that Merovingian Gaul, like the late Roman Empire of the previous centuries, hosted multiple, entangled networks of social and political interconnections. This chapter considers how we can set about contemplating both the limitations and value of the evidence we have. Comparison with contemporary Egypt, from which letters are preserved both in manuscript tradition (as with Gaul) and as papyri originals, evokes the possibility of envisaging Merovingian Gaul quite differently from our received image. The extant evidence for letters is surveyed, including “literary” collections of letters, letters preserved in other types of texts, and the extensive number of descriptions of letter exchange in narrative texts. The chapter includes the first checklist of more than 500 extant letters and a list of narrative sources, including the first complete list of references to letters in the works of Gregory of Tours.