The term "public opinion" means the feeling or sentiment shared by most people, the voice of the people. This definition may be simple, but it is often difficult to determine what the public's opinion is on any given issue and how to interpret its meaning. This two-volume encyclopedia defines and discusses the history and development of public opinion as a concept in democracy, major public opinion controversies in American politics, and the science and methods of opinion polling. Over 170 signed entries explain the major concepts, people, historical events, organizations, practice and theory, and measurement methods of public opinion and political opinion polling in the United States.