A sustained prose exegesis and collection of related essays that illuminate the medieval narrative poem through close, canto-by-canto glosses. The text alternates literal and allegorical readings, clarifies difficult vocabulary and syntactic forms, cites classical and theological authorities, proposes textual emendations, and evaluates moral and rhetorical implications. Philological observations and scholastic reasoning accompany interpretive arguments, while extended treatments of particular passages examine imagery, structure, and the graduated meanings of key terms for readers and students.