Amid all the hype about 'big data' and analytics in Obama's presidential campaigns, one key story hasn't been told in full: how the Obama team built a sprawling and vibrant field organization almost entirely out of volunteer labor. Han and McKenna recount the successes and struggles of this effort, drawing on extensive and illuminating interviews with everyone from senior staff to many of those volunteers. Their account shows how a winning campaign depends as much on old-fashioned shoe leather as on statistical models and multi-million dollar advertising sprees. This is a book that both scholars and practitioners of campaigns should read.