I’m delighted to participate in this session, especially since it was during a childhood visit to Reims that I first fell in love with Gothic architecture. Enthralled by the cathedral, I bought a guidebook in which I found the famous illustration by Viollet-le-Duc seen at right, showing the building idealized and completed with seven spires. My discovery of this image planted the seed that grew into my dissertation on Gothic spires, and my first book. Although Reims figured into that book, it was not at center stage. And since no original design drawings for Reims Cathedral survive, I largely passed over it in my more recent book on the geometry of Gothic drawings. This, therefore, is my first talk on the building that was my first love. That, by itself, makes me pretty excited. But I am excited for more substantive reasons, too, since I’ve recently begun to resolve some of the questions that first fascinated me all those years ago. In particular, I think I now understand the geometrical design principles that governed the layout of the cathedral in both plan and elevation. And this, in turn, has given me a new perspective on the development of its north transept, a part of the building that has always confused me. The image at left, as many of you have probably guessed, shows a version of the north transept that I have PhotoShopped, in the somewhat permissive spirit of Viollet-le-Duc, to reflect what I think may have been the design intention in the early thirteenth century.