Taylor Carlson examines how political information spreads through social networks - both online and offline - and how this 'grapevine' differs from traditional mass media in ways that distort democratic knowledge. Drawing on extensive research into how people learn about politics from friends, family, and social media contacts, Carlson shows that socially transmitted information tends to be more politically skewed, less accurate, and more emotionally charged than news from professional journalists. Yet this information is also more persuasive and more likely to prompt political action, precisely because it comes from trusted sources. The book traces how the shift from broadcast media to social sharing has transformed the American information environment, with consequences for what citizens know and how they participate. Carlson's research reveals that people systematically misperceive how much they learn through social channels versus traditional media, underestimating the grapevine's influence on their beliefs. The book examines implications for political campaigns, which increasingly try to trigger social sharing rather than deliver messages directly. It also considers what can be done to improve the quality of socially transmitted information without restricting the social connections that make democracy possible. For anyone concerned about misinformation and polarization, Carlson's work provides rigorous analysis of how information actually flows through democratic societies.