Online news sites play an ever-pervasive role in the daily gathering and flow of political information. Media has always played an intermediary role in the way that citizens receive and process news, but, with the speed of information transmission, the segmentation of news sources, and the rise of citizen journalism, issues of authority, audience, and even the definition of "news" have shifted and become blurred. News on the Internet synthesizes research on developing and current patterns of online news provision with the literature on traditional, offline media to create a conceptual map for understanding the way that public affairs and news are presented and consumed on the internet. Tewksbury and Rittenberg look at the dual role of the internet as a source of authoritative news and as a vehicle for citizens in contemporary democracies to create and share political information. Throughout, they address the tension between the benefits of internet news provision, specifically increased citizen engagement, and the negative, perhaps counterintuitive, effects: the fragmentation of knowledge and polarization of opinion in contemporary democracies. News on the Internet focuses on these points of conflict and contradiction in the online news environment and offers conclusions and predictions for how these phenomena will develop in the future.