This was a transformative period in English history. In 1783 the country was at one of the lowest points in its fortunes, having just lost its American colonies in warfare. By 1846 it was once more a great imperial nation, as well as the world's strongest power and dominant economy, having benefited from what has sometimes (if misleadingly) been called the "first industrial revolution." In the meantime it survived a decade of invasion fears, and emerged victorious from more than twenty years of "war to the death" against Napoleonic France. But if Britain's external fortunes were in the...