LONDON renews the pleasures of urban life. It is a city one can walk in; its history is written in its streets. Paris has its grand public architecture, but the bulbous tops of the Louvre or the high mansard roofs that form a continuous line along the grands boulevards can be oppressive, and the heavy gates framing the street lines of the old buildings bar one from the charming courtyards lying within the walls. Tokyo is shapeless and ugly, coming alive only at night in the carnival profusion of neon signs and in the narrow, twisting streets of the entertainment centers in the heart of each district or at the nodules of the railways terminuses.  New York is bustle and noise and dirt, yet its main streets, like Madison Avenue or Fifth Avenue, go surprisingly dead after 10 o’clock at night. Its marvel is the massed, powerful skyline visible from Brooklyn Heights or the Triborough Bridge or the Jersey Palisades; it is impressive, but only at a distance.