The Logic of Connective Action explains the rise of a personalized digitally networked politics in which diverse individuals address the common problems of our times such as economic fairness and climate change. Rich case studies from the United States, the United Kingdom and Germany illustrate a theoretical framework for understanding how large-scale connective action is coordinated. In many of these mobilizations, communication operates as an organizational process that may replace or supplement familiar forms of collective action based on organizational resource mobilization, leadership, and collective action framing. In some cases, connective action emerges from crowds that shun leaders, as when Occupy protesters created media networks to channel resources and create loose ties among dispersed physical groups. In other cases, conventional political organizations deploy personalized communication logics to enable large-scale engagement with a variety of political causes. The Logic of Connective Action shows how power is organized in communication-based networks, and what political outcomes may result.