A continued public response to the fourth edition of this collection of<br > architectural walking tours， combined with major additions to the<br > Downtown and Michigan Avenue areas of Chicago， has prompted its<br > update and revision.<br > The WALKS proposed here have been selected to present Chicago as<br > a great cosmopolitan city as well as a collection of local communities， tied<br >together by an intricate web of transportation that makes them accessible<br >to the pedestrian for a closer view.<br > Since Chicago is a vast outdoor museum of great architecture created<br >in about one hundred years， the major focus of the WALKS is architec-<br >tural. From 1883 to 1893 the "Chicago school of architecture" came into<br >being. During that decade a whole galaxy of buildings appeared， reaching<br >the unprecedented heights of 12， 14， 16， and 23 stories. The architects<br >of the Chicago school employed a new type of construction: the iron<br >skeleton， at that time called quite simply Chicago construction. They<br >invented d new kind of foundation to cope with the problems of the<br >muddy ground of Chicago: thefloatingfoundation. They introduced the<br >horizontally elongated window: the Chicago window. They created the<br >modern business and administration building. And around the turn of<br >the century， the so-calledlrairie house came into being here.<br > Of equal significance is the current work of Chicago architects， often<br >characterized as a continuation of the Chicago school. Its pure forms，<br >horizontally elongated windows， and rugged strength are still to be seen<br >in many of today s buildings. Architects of the present， however， have<br >not hesitated to experiment with their own designs and materials.<br >Though Mies van der Rohe s "glass houses" on North Lake Shore Drive<br >and Helmut Jahn s State of Illinois Building may be considered the<br >ultimate development of certain trends of the Chicago school， the<br >cylindrical towers of Marina City， with their concrete slab construction，<br >circular balconies， and pie-shaped rooms， bear little resemblance. Nor<br >does the facade of the Henry Hinds Laboratory for the Geophysical<br >Sciences Building at the University of Chicago--though the older school<br >of architects would approve the functional origin of the new features.<br > Complete coverage of buildings worth noting in Chicago cannot<br >possibly be attempted， especially in view of the size of the city. While<br >following the routes proposed here， the pedestrian will many times come<br >across other interesting or beautiful buildings. The frequency with which<br >this may happen is only another tribute to the endless vitality of this<br >tremendous city.<br >