Marco Polo describes to Kublai Khan the cities he has visited: cities of memory, cities of desire, cities of signs, hidden cities, thin cities, trading cities. Each description is a page or two of crystalline prose, and gradually you realize all the cities may be one city, or no city, or the city of the mind itself. Calvino wrote this as a meditation on language, on memory, on the relationship between words and things. The book has no plot in any conventional sense; it has patterns, variations, a musical structure. Readers return to it like returning to a city they have never left. Each visit reveals different streets.