No scholarly effort is ever conducted without heavy indebtedness to others. This is particularly true of efforts that rest as heavily as this one does upon data collection efforts carried out by others. Our largest debt is, of course, to M. Watt Espy. Without his continuing effort, this study would have been impossible. We are profoundly grateful to him and hope that our efforts prove to be a credit to his work. We are indebted as well to the National Science Foundation for providing the support required to make the initial version of the collection available for general use. We also are grateful to John Ortiz Smykla for his work in preparing the collection for use. We are pleased to once again express our indebtedness to the Inter-university Consortium for Political and Social Research for maintaining and providing access to the computerreadable version of the collection and to the collection of historical census data. Victoria Schneider contributed to the preparation of the data collection for use and first brought it to the attention of one of us. Although she decided not to participate in the effort reported here, her early assistance was of considerable value. We are grateful as well to Erik W. Austin of the Inter-university Consortium for Political and Social Research who advised us of characteristics of the various data collections we have used. Special thanks also to Walter Stubbs, government documents librarian, and to other members of the staff of Morris Library at Southern Illinois University at Carbondale.

James Q. Graham read an early version of our manuscript and made many helpful comments and suggestions. We appreciate his efforts. We also are grateful to several anonymous readers. Although we were unable or unwilling to follow all of the suggestions, their comments made this a better book. The two authors are, of course, equally responsible for its shortcomings.