By using a broad selection of ‘commentary discourse’, this chapter looks at the practice of reading, teaching and composing texts whose purpose is (partly) to explain older texts. Such commentaries, which can take various and sometimes unexpected forms, are of paramount importance for understanding the Byzantine intellectual and cultural framework of literary production, not only as a system of ‘authoritative mimesis’ but also as a system of ‘subversive anti-mimesis’. Thus, the chapter examines paraphrases of the Iliad, grammatical exercises such as the schede of Theodore Prodromos, lives of saints with integrated gnomologia, laudatory orations and novels, poetical treatises of political admonition (e.g. the anonymous Spaneas), scholia on ancient authors (like those produced by John Tzetzes on Aristophanes and Lycophron or by Eustathios on the Homeric poems), but also large-scale commentaries on Byzantine hymnongraphy (e.g. by John Zonaras on John of Damascus), philosophical and theological commentaries (Michael of Ephesos on Aristotle or Niketas of Herakleia on the Psalms). These texts represent different and yet interrelated discourses that highlight the key role of ‘commentary’ as a hermeneutic tool of and testimony to a broad spectrum of sociocultural and literary tensions within the longue durée of the Komnenian era.