Hav, by Jan Morris. This edition has an introduction by Ursula K. Le Guin, which is what drew me to it. Amusing anecdote from that intro: due to Morris's more typical work as a travel writer, many people wanted to know how they could "book a cheap flight" to this enchanting city. Le Guin dryly observed that, due to many people's poor understanding of fiction, they did not realize that it is not the destination that is the problem, but the origin of the trip: "You couldn't get there, in fact, from London or Moscow, but from Ruritania, or Orsinia, or the Invisible Cities, it was simply a matter of finding the right train." What a loss, now that she is gone!
BTW, I am enjoying the book, apart from Le Guin's scintillating intro!