Voting has become truly an interdisciplinary object of investigation in recent years. Historians, statisticians, social psychologists, sociologists, and political scientists have focused their attention on electoral behavior, individually or in teams. Such studies have been principally the work of scholars in the traditional Western democracies—Britain, France, Norway, Sweden, the United States—and fall roughly into three patterns. One approach has been to analyze trends in group voting behavior on the basis of census and election statistics, and frequently poll data as well, in a search for meaningful correlations between voting trends and socio-economic factors. The work of Siegfried and, more recently, Goguel in France, of Heberle in Germany, Tingsten in Sweden, and Gosnell and Key in the United States belongs in this category. A second approach has been descriptive, identified in recent years particularly with Nuffield College at Oxford. The Nuffield studies of elections in Britain, France, Ireland, Poland, Italy, and Africa have focused on the efforts of candidates and parties to influence voters in a particular electoral campaign. They are intended primarily to be contributions to contemporary history and works of reference for future historians. Lastly, we have the investigations associated, in particular, with the Bureau of Applied Social Research at Columbia University and the Survey Research Center at the University of Michigan. These have focused on the political images and electoral behavior of individual voters and, particularly, on changes in their attitudes during a campaign and the reasons for such changes. They have relied, almost exclusively, on survey research methods which involve questioning a panel of representative voters at length before and after an election and, lately, even over a period of several years and elections.