This chapter describes the contours of the epistemic crisis in media and politics that threatens the integrity of democratic processes, erodes trust in public institutions, and exacerbates social divisions. It lays out the centrality of partisanship, asymmetric polarization, and political radicalization in understanding the current maladies of political media. It investigates the main actors who used the asymmetric media ecosystem to influence the formation of beliefs and the propagation of disinformation in the American public sphere, and to manipulate political coverage during the election and the first year of the Trump presidency, , including “fake news” entrepreneurs/political clickbait fabricators; Russian hackers, bots, and sockpuppets; the Facebook algorithm and online echo chambers; and Cambridge Analytica. The chapter also provides definitions of propaganda and related concepts, as well as a brief intellectual history of the study of propaganda.