[My] original plan was to regard this history as a single unified work, and the corresponding intention of the University of Chicago press was to publish it in a single volume under the title Chicago since 1910, A number of factors, however, suggested that there would be advantages to both reader and publisher in splitting the book into two separate parts. The long texts, the total of 176 plates and line cuts, the extensive tables and index, and the formidable bibliography would together have resulted in a book of nearly unmanageable size and discouraging price to the reader, and of prohibitive cost, in this age of tight budgets, to the publisher. Publication in two volumes, though it would mean no saving in total expense, at least had the merit of spreading it over a longer period of time. I doubt that the division adversely affects the continuity of the text-indeed, it throws into sharper relief the drastic discontinuity in urban development that came from the long hiatus in building caused by the depression of the thirties and the war that followed it. Those years marked the turning point for the American city-from expansion, confidence, and civic resurgence to economic and cultural decline. The two volumes thus treat two markedly different manifestations of the modern urban world.