The medieval sermon provides the focus for the first volume of Disputatio because it often expresses the concerns of various intellectual milieux, such as the university, Church or court, and attempts to convey those concerns to other parts of medieval society.

Speculum Sermonis is an anthology of essays about medieval sermons in the Christian East and West. It aims to reveal precisely how sermons inform different disciplines (for instance, social and Church history, literature, musicology) and how the methodologies of different disciplines inform sermons. Sermons can, for instance, provide evidence for a reconstruction of medieval liturgy; reciprocally, the field of liturgiology investigates sermons as one aspect of Church performance. The volume's title image of the mirror and the reference to medieval specula convey the idea of multiple reflections: the sermons' on culture and the disciplines' on sermons. Because the contributors to Speculum Sermonis come from a variety of fields, the essays here collectively provide a rich historical and contemporary academic context for reading the medieval sermon.

In addition to essays from across the fields, a number of which establish conclusions transcending disciplinary boundaries, Speculum Sermonis includes an introduction defending interdisciplinary study of sermons and an authoritative bibliography covering both primary and secondary resources for medieval sermons. A unique feature of the volume is the inclusion of response papers to the essays in each of the sections, in the spirit of the book series title Disputatio.