There is a building constellation in Siena which has purportedly been built over some eighteen centuries. It has been growing by accretion, swallowing up in fits and starts ancient buildings and even streets, and incorporating them entire into its fabric. At the very bottom of this vast structure cave dwellings can be found, while at the top ample loggias are still being built to overlook the Tuscan countryside. For centuries the city hospital grew and adjusted its fibrous body to this concoction of stone, mud, iron, lime, wood, sand, glass, and darkness. Many a citizen of Siena who was born in the hospital died there willingly, too. From its awkwardly decorated flank facing the cathedral, to the mass of residual protrusions and windows facing the fields, this protean monster is still throbbing with life that started it on its journey. And if I were ever to search for a physical model of my book, I would gladly point at the hospital in Siena as its closest substitute.