A High Gothic cathedral
Nave and aisles, transept with crossing and flèche, choir with ambulatory and radiating chapels, flying buttresses, and a twin-towered west front, shown whole or in section.
The rules it illustrates
Concentrate the loads; fill the rest with glass. Gather the weight and thrust of the vaults onto a few points by ribs, carry them down piers and out across the aisles by flying buttresses to external buttress piers, and the wall between the supports carries almost nothing, so it can be opened into windows.
The chevet: ambulatory and radiating chapels. End the choir in a semicircle of piers; wrap an aisle (the ambulatory) around it, and open a ring of chapels off the ambulatory, each with its own altar and windows, so that the east end steps down in tiers of roofs and buttresses.
Where it appears in the book
In the styles Gothic.
In the chapters Romanesque and Gothic.