Ancient epistolary fiction is a still largely under-explored field of research, at the intersection of studies on epistolography and on pseudepigraphy. The present volume sketches out a broad panorama of ancient fiction in letters. It covers a large period of time up to late Antiquity, with a main focus on letters from the imperial era. Epistolary fiction is examined as a mainly Greek phenomenon (there are few Latin equivalents) that was characteristic of both pagan and Christian literature. The material investigated falls within two categories: fictional letter collections from well-known authors of the Second Sophistic and their successors (Lucian, Alciphron, Philostratus, Aristaenetus); letters attributed to famous historical or legendary characters (pseudonymous letters). Focusing on the specific features of epistolary fiction, the book aims to analyse its forms, its functions as well as its effects. It gathers a series of 11 state-of-the art essays, all tackling the same important issues: the manuscript and printed tradition, the form of epistolary fictions and the universe they build, the arrangement of the letters and their overall structure, the relation between the author and his external readers.