This volume explores the themes of authorship and authenticity - and connected issues - from the Classical Antiquity to the Renaissance. Its reflection is constructed within a threefold framework. A first section includes topics dealing with dubious or uncertain attribution of ancient works, homonymous writers, and problems regarding the reliability of compilation literature. The middle section goes through several issues concerning authorship: the balance between the author's contribution to their own work and the role of collaborators, pupils, circles, reviewers, scribes, and even older sources, but also the influence of different compositional stages on the concept of 'author', and the challenges presented by anonymous texts. Finally, a third crucial section on authenticity and forgeries concludes the book: it contains contributions dealing with spurious works - or sections of works - , mechanisms of interpolation, misattribution, and deliberate forgery. The aim of the book is therefore to exemplify the many nuances of the complex problems of authenticity and authorship of ancient texts.