Formed in 1839, the Anti-Corn Law League was one of the most important campaigns to introduce the ideas of economic liberalism into mainstream political discourse in Britain. Its aspiration for free trade played a crucial role in defining the agenda of nineteenth-century liberalism and shaping the modern British state. Its faith in the free market still resonates in Britain's public policy debates today. This is the first comprehensive study of the League which makes use of recent methodological developments in social history.