In this dissertation, I investigate a moment of immense significance for cultural and literary history: the rise of the English public theater as a form of mass entertainment and the flourishing of plays designed specifically to engage and move a rapidly emerging public audience. Like all new media forms, the public theater generated both enthusiasm about its potential to instill civic virtue in audiences and acute anxiety about its capacity to defraud them. I demonstrate how playwrights such as Christopher Marlowe, William Shakespeare, Ben Jonson, Thomas Middleton, and Philip Massinger navigated this difficult landscape, poised between visions of the public theater as a center for independent thought and deliberation and as a space for the dissemination of propaganda. In particular, I argue that much of their political drama constitutes a metatheatrical reflection on the promises and the perils of theatrical mass media and, specifically, its capacity to educate or manipulate the public. These playwrights perceived the dangers and opportunities of the theater, I suggest, through the lens of classical rhetoric, a field of study intimately related to early modern literary production and deeply concerned about the proper ways of addressing mass audiences. A Renaissance rhetorical education allowed students both to identify the tools with which orators move or manipulate their audiences and to employ those tools for themselves. Scholars frequently consider early modern drama in terms of rhetoric, detailing how rhetorical education influenced the composition of plays, how playwrights employed rhetorical tropes and figures, and how they thought about rhetorical ethics. I take such analyses a step further by connecting playwrights' debates about the ethics of rhetoric with very similar cultural debates about the ethics of theatrical mass media. Where are the lines between persuasion and coercion, education and indoctrination? Is the practice of rhetoric—or the performance of theater—about a collaborative search for truth or about controlling the unruly masses? "Propaganda and Deliberation: The Rhetoric of the Early Modern English Public Theater" illustrates how these rhetorical-ethical dilemmas animated early modern dramatic literature and how playwrights like Marlowe, Shakespeare, and Jonson drew on their extensive rhetorical training to meet a moment of profound media shift. I argue in particular that these playwrights sought to transform the theater into a site of rhetorical and political education, one that would inculcate deliberative habits of mind in its audience members and create a citizenry resistant to indoctrination. In dramas that are designed to reveal and subvert the strategies of theatrical propaganda and that employ rhetorical tools like the argumentum in utramque partem (or the "argument on both sides" of a question), playwrights seek to develop their audiences' political judgment. Even as they celebrate the value of deliberation and debate, however, these dramatists also recognize that their methods might be appropriated by the elite for the purposes of political agitprop or otherwise authoritarian forms of political education. Their plays worry about the ways in which rhetorical mindsets may dangerously destabilize spectators' sense of truth or moral clarity and about the ways in which bad actors, so to speak, can use rhetorical-theatrical tools to manipulate the masses. Rather than creating subjects resistant to indoctrination, the deliberative tools of the theater, these dramatists recognize, could be used to do exactly the opposite. My dissertation investigates, in short, what happens when the power of early modern rhetoric, in all its conflicted traditions, encounters the early modern stage, in all of its capacity to influence the masses.