Walkers are 'practitioners of the city,' for the city is made to be walked. A city is a language, a repository of possibilities, and walking is the act of speaking that language, of selecting from those possibilities. Just as language limits what can be said, architecture limits where one can walk, but the walker invents other ways to go.

Cities have always offered anonymity, variety, and conjunction, qualities best basked in by walking: one does not have to go into the bakery or the fortune-teller's, only to know that one might. A city always contains more than any inhabitant can know, and a great city always makes the unknown and the possible spurs to the imagination.

In great cities, spaces as well as places are designed and built: walking, witnessing, being in public, are as much part of the design and purpose as is being inside to eat, sleep, make shoes or love or music. The word citizen has to do with cities, and the ideal city is organized around citizenship -- around participation in public life.

Whose maps are we trying to read? And what are we trying to draw? It's so common to live in a place without truly knowing its history, its systems, and the people who are different from you and who move through different versions of the city.

I have been both a ghost and haunted in the city I love.

A city always contains more than any inhabitant can know, and a great city always makes the unknown and the possible spurs to the imagination.