This Director's Lecture by Quentin Skinner, Barber Beaumont Professor in Humanities at Queen Mary's University, London, commemorated the opening of the Neubauer Collegium's permanent home on campus. The concept of individual freedom is usually understood in negative terms as absence of interference or constraint. Skinner argued that this orthodoxy is in need of qualification and perhaps abandonment. Skinner began his lecture by noting that, because the concept of interference is such a complex one, there has been much dispute even within the liberal tradition about the conditions under which it may be legitimate to claim that freedom has been infringed. Furthermore, some writers challenge the liberal tradition by insisting that its emphasis on non-interference leaves us without any grasp of the content of human freedom. Skinner went on to suggest that both these traditions of thought arguably fail to recognize the centrality of a different element in the idea of personal liberty. His lecture concluded with an attempt to excavate this rival and largely occluded tradition of thinking, and with some reflections on its special importance in democratic societies.