It’s basically all a discussion between the characters of Marco Polo and the Emperor Khan, and has a framework very much like Scheherezade, in that is actually a nest of stories within a larger story. Little distinct vignettes that explore the relation between the city and memory and desire, signs and human nature, but all, ultimately, about the one place, Venice. (Or indeed every city.)
I’ve mentioned that this novel was a bit of an influence, and I would suggest that anyone who is creating a fantasy city should take a loot at this book, simply because of the dreamlike explorations of the psycho-geography of urban spaces. A city is more than walls in which characters shuffle back and forth. There’s a relationship and a mood and a tension, and the city itself generates some quality over and above the architecture and people—some emergent property.
I’ve always maintained that fantasy fiction, in my opinion, should be able to challenge us by using its more surreal nature to distort particular realities in a way that really hits home. That’s when it’s working best for me, and an understanding of the way cities affect people and are affected by them can only make for a deeper secondary-world literature. That’s what this book does so well.