This issue of "Zeitsprunge" collects a variety of theoretical approaches to and exemplary readings of medieval and early modern practices of commentary from the point of view of Arabic, Latin, Jewish, English, German, and Romance Studies. Since antiquity, commentaries have accompanied sacred, cultural, and literary texts, serving to justify their relevance and canonicity. They have been instruments for the transmission of legal and religious norms and values, as well as purveyors of ancient knowledge which has to be preserved verbatim, and yet be kept open for future communication. At times, the commentary even attains a sovereignty of interpretation that can supersede or push aside any original intentions of the text. Thus, the study of commentary is key to describing aspects of authority, institutionality, creativity, and textual empowerment from a comparative perspective. The articles in this issue highlight the role that the study of commentary can play in a historical understanding of premodern and early modern textuality, epistemology, and mediality.