Sasha Issenberg chronicles how political campaigns have been transformed by social science and data analytics. He follows the academics, consultants, and operatives who developed field experiments, micro-targeting, and behavioral science approaches to voter mobilization. The book traces innovations from early experiments testing whether canvassing actually increased turnout through the Obama campaign's sophisticated use of data to the ongoing competition between parties to find technological edges. Issenberg gained access to practitioners reluctant to share their methods, revealing techniques for identifying persuadable voters, designing effective messages, and allocating resources. The book raises questions about privacy, manipulation, and whether campaigns that know so much about voters might undermine democratic deliberation. But Issenberg's primary interest is in how political technology has evolved and what difference it makes. For anyone interested in campaigns, elections, or the application of social science to practical problems, this book provides an engaging account of a largely invisible industry.