This major work surveys the historical roots, theoretical foundations, and normative claims of 20th-century conceptualizations of public opinion. It reanalyzes leading traditions, such as those of Lippmann, Dewey, and Noelle-Neumann, and reinvents some unjustly ignored ones, such as Toennies, Harrisson, and Wilson. The book critically examines popular modern research strategies such as polling and the 'spiral of silence' model and looks at the role of mass media in the formation and expression of public opinion.