The growth of technological and scientific knowledge in the past two centuries has been the overriding dynamic element in the economic and social history of the world. Its result is now often called the knowledge economy. But what are the historical origins of this revolution and what have been its mechanisms? In , Joel Mokyr constructs an original framework to analyze the concept of "useful" knowledge. He argues that the growth explosion in the modern West in the past two centuries was driven not just by the appearance of new technological ideas but also by the improved access to these ideas in society at large--as made possible by social networks comprising universities, publishers, professional sciences, and kindred institutions. Through a wealth of historical evidence set in clear and lively prose, he shows that changes in the intellectual and social environment and the institutional background in which knowledge was generated and disseminated brought about the Industrial Revolution, followed by sustained economic growth and continuing technological change. Mokyr draws a link between intellectual forces such as the European enlightenment and subsequent economic changes of the nineteenth century, and follows their development into the twentieth century. He further explores some of the key implications of the knowledge revolution. Among these is the rise and fall of the "factory system" as an organizing principle of modern economic organization. He analyzes the impact of this revolution on information technology and communications as well as on the public's state of health and the structure of households. By examining the social and political roots of resistance to new knowledge, Mokyr also links growth in knowledge to political economy and connects the economic history of technology to the New Institutional Economics. provides crucial insights into a matter of fundamental concern to a range of disciplines including economics, economic history, political economy, the history of technology, and the history of science.