There is a book I would like to recommend as a virtual "sequel" to this one. The Origins of the Urban Crisis by Thomas Sugrue. While Cohen's book is about the creation of the New Deal coalition in the factory neighborhoods and towns of Chicago, Sugrue's book is about the disappearance of the factories and the departure from the Democratic coalition in the 1960s of the same groups who joined it in the 30s. Sugrue's book also won a Bancroft prize and if you like one you will surely like the other.
Cohen does not create a delineation between immigrants that came to the area and natives of the Chicago area, which goes a long way in terms of bias. She covers African-Americans, Polish, Italians, and Jews without being critical one way or the other. Each chapter seems to be able to live by itself, which gives the book a flavor of being a compendium of papers instead of a conjoined work. All in all, Cohen does a wonderful job examining Chicago and Chicagoans whatever their ethnicity may be.