The argument of this book is that, with a long decline in manufacturing profitability, capitalism has turned to data as one way to maintain economic growth and vitality in the face of a sluggish production sector. In the twentyfirst century, on the basis of changes in digital technologies, data have become increasingly central to firms and their relations with workers, customers, and other capitalists. The platform has emerged as a new business model, capable of extracting and controlling immense amounts of data, and with this shift we have seen the rise of large monopolistic firms. Today the capitalism of the high- and middle-income economies is increasingly dominated by these firms, and the dynamics outlined in this book suggest that the trend is only going to continue. The aim here is to set these platforms in the context of a larger economic history, understand them as means to generate profit, and outline some of the tendencies they produce as a result.