Grassroots organizing and collective action have always been fundamental to American democracy but have been burgeoning since the 2016 election, as people struggle to make their voices heard in this moment of societal upheaval. Unfortunately much of that action has not had the kind of impact participants might want, especially among movements representing the poor and marginalized who often have the most at stake when it comes to rights and equality. Yet, some instances of collective action have succeeded. What's the difference between a movement that wins victories for its constituents, and one that fails? What are the factors that make collective action powerful? Prisms of the People addresses those questions and more. Using data from six movement organizations—including a coalition that organized a 104-day protest in Phoenix in 2010 and another that helped restore voting rights to the formerly incarcerated in Virginia—Hahrie Han, Elizabeth McKenna, and Michelle Oyakawa show that the power of successful movements most often is rooted in their ability to act as "prisms of the people," turning participation into political power just as prisms transform white light into rainbows. Understanding the organizational design choices that shape the people, their leaders, and their strategies can help us understand how grassroots groups achieve their goals. Linking strong scholarship to a deep understanding of the needs and outlook of activists, Prisms of the People is the perfect book for our moment—for understanding what's happening and propelling it forward.