"During the four centuries when printed paper was the only means by which texts could be carried across time and distance, everyone engaged in politics, education, religion, and literature believed that reading helped to shape the minds, opinions, attitudes, and ultimately the actions, of readers." "William St. Clair investigates how the national culture can be understood through a quantitative study of the books that were actually read. Centred on the romantic period in the English-speaking world, but ranging across the whole print era, he reaches startling conclusions about the forces that determined how ideas were carried, through print, into wider society." St. Clair provides an in-depth investigation of information, made available here for the first time, on prices, print runs, intellectual property, and readerships gathered from over fifty publishing and printing archives. He offers a picture of the past very different from those presented by traditional approaches. Indispensable to all students of English literature, book history, and the history of ideas, the study's conclusions and explanatory models are highly relevant to the issues we face in the age of the internet.