"In Twenty Minutes in Manhattan, Michael Sorkin, an architect and critic, makes like Jacobs and immerses himself in the rhythms and patter of the street. He has shaped his book according to the contours of his daily stroll across a dozen or so blocks of Lower Manhattan, from the top floor of his five-story Greenwich Village walk-up to his office in TriBeCa. Walking, Sorkin writes, is 'a natural armature for thinking sequentially,' providing opportunities for heady musings on all manner of city life. Yet his peripatetic narrative is anything but linear.