The “public sphere”—an idea with deep roots in the European enlightenment—has always been a contested concept in American culture and society. American intellectuals, artists, politicians, and activists have stressed the non-unitary, diversified, and oppositional dynamics of all things public. From the early days of the American republic, competing interest groups and commercial mass media (first newspapers, novels, and the theater, then radio, television, and the internet) have worked to pluralize public speech and public action—and ultimately the notion of “publicness” itself. This essay collection explores the public sphere in North America as a multi-agential, commercially embattled, highly mediated, and ultimately trans-nationalized aggregate of publics and counterpublics. The contributors present innovative theoretical and historical assessments of American counter/publics across an array of fields including social activism, political communication, literary discourse, and contemporary mass media.