T pIHE Central Business D)istrict (CBD) of the American city is so familiar to the average citizen that he is likely to take it for granted. Under one name or another, it is thought of as an area of urban concentration that has been in existence since the beginning of the city and that will last as long as the city endures. But the CBD, as it is known today, is relatively modern, and its place in the city of tomorrow is a subject of wide debate. This uncertainty is based upon the many problems with which planners and other students of the city are grappling. To meet these problems, a better understanding of the district is necessary, and this cannot be attained through concentrating on any one city. Instead, comparative studies are needed, just as they are in many other phases of urban research. This paper is one of the products of such a study, dealing with the CBDs of nine cities-Worcester, Massachusetts; Grand Rapids, Michigan; Salt Lake City, Utah; Tacoma, Washington; Sacramento, California; Phoenix, Arizona; Tulsa, Oklahoma; Mobile, Alabama; and Roanoke, Virginia. A comparison of CBDs involves sev-