This introduction presents an overview of key concepts discussed in the subsequent chapters of this book. The book maps the intellectual formation of English plebeian radicalism and Scottish philosophic Whiggism, and examines their associated strategies of critical engagement with the cultural, social and political crises of the early nineteenth century. It is a story of the making of a wider British public sphere out of the agendas and discourses of the radical and liberal publics that both shaped and responded to them. The book also engages with the Marxist tradition of British cultural studies represented in the work of E. P. Thompson, Raymond Williams and Richard Johnson, in order to frame key issues of intellectual and cultural agency during romantic period. It concludes with a brief discussion of two articles by Cobbett in the Political Register from the end of 1830 responding to the Captain Swing rebellion in the agricultural districts of the South of England.