Freedom has become perhaps the most central value in current political debate. The lecture tries to clarify what is involved in invoking freedom as a justification. Quentin Skinner is Regius Professor of Modern History and a Fellow of Christ's College. His interests lie in the intellectual history of early-modern Europe, and he specialises in the Renaissance and in seventeenth-century political philosophy - in particular the philosophy of Thomas Hobbes, on which he has published two books and numerous articles.