An in-depth exploration of social media and emergent technology that details the inner workings of modern propaganda. Until recently, propaganda was a top-down, elite-only system of communication control used largely by state actors. Today, as Samuel Woolley argues, social media has democratized propaganda, allowing nearly anyone to launch a fairly sophisticated, computationally enhanced, propaganda campaign. Woolley shows how social media, with its anonymity and capacity for automation, allows political groups to create the illusion of popularity through computational tools (such as bots) and human-driven efforts (such as sockpuppets-real people assuming false identities online-and partisan nano-influencers) and then either create a bandwagon effect by bringing the content into parallel discussions with other legitimate users, or mold discontent for political purposes. Drawing on eight years of original international ethnographic research among the people who build, combat, and experience these propaganda campaigns, Woolley presents an extensive view of the evolution of computational propaganda, offers a glimpse into the future, and suggests pragmatic responses for policy makers, academics, technologists, and others.