The order of the fragments making up the Canterbury Tales and the structure of that collection have long been questioned. Ann W. Astell proposes that Chaucer intended the order that is preserved in what is known as the Ellesmere manuscript. In supporting her claim, Astell reveals a wealth of insights into the world of medieval learning, Chaucer's expected audience, and the meaning of the Canterbury Tales. Astell examines the conventions of medieval learning familiar to Chaucer and discovers in two related topical outlines, those of the seven planets and of the divisions of philosophy, an important key. Assimilated to each other in a kind of transparent overlay, these two outlines, which were frequently joined in the literature with which Chaucer was familiar, accommodate the actual structural divisions of the Tales (in the order in which they appear in the Ellesmere manuscript), define the story blocks as topical units, and show the pilgrims' progress from London to Canterbury to be simultaneaously a planetary pilgrimage and a philosophical journey of the soul. The two patterns, Astell maintains, locate Chaucer's work in relation to that of both Gower and Dante, philosophical poets who shared Chaucer's relatively novel status as lay clerk, and who were, like him, members of the educated, secular bourgeoisie. The whole of the Canterbury Tales is thus revealed to be in dialogue with Gower's Confessio and Dante's Paradiso. Indeed, it represents an elaborately detailed response to the images used, and the stories related, in Dante's successive heavens.