This authoritative new edition of the ancient scholia to Sophocles' Trachiniae is designed to replace the corresponding part of the Teubner text published in 1888. It is the first to rely on a complete scrutiny of the sources of the text and the conjectural activity of scholars, but is also characterised by a fresh methodological approach: the transmission of scholia is prone to creating different versions of basically the same material, and to making conflations of originally distinct entities; in the English preface these transmissional peculiarities guide the editor in establishing a methodology which is appropriate both for analysing the manuscript tradition and composing the critical text of the Trachiniae scholia. By applying this working tool, the editor is the first to restore the scholia to the Trachiniae in a textual state which is arguably the earliest we can recover, and is free of contradictions, unacceptable repetitions, and hybridisation or blending of elements from different versions. The critical text is accompanied by a detailed apparatus criticus, and is contextualised in its scholarly tradition by means of a rich collection of parallel passages. Extensive indices are provided at the end of the book.