Ideology has never before been so much in evidence as a fact, and so little understood as a concept, as it is today.In this now classic work, originally written for both students and for those already familiar with the debates around the concept, the celebrated literary theorist Terry Eagleton unravels its many definitions, exploring its tortuous history from the Enlightenment to the present. A limpid account of the thought of key Marxist thinkers, as well as that of philosophers from Schopenhauer and Nietzsche to Freud and the post-structuralists, and a political reformulation of a vital set of ideas, Ideology: An Introduction is an essential text by one of our most important contemporary critics.