4.2 Further reading
The complete text of Isaiah Berlin's essay ‘Two Concepts of Liberty’ is contained in his Four Essays on Liberty (Oxford University Press, 1969). This book also contains an essay on John Stuart Mill's theory of liberty. A wider-ranging selection of Berlin's essays is The Proper Study of Mankind (Pimlico, 1998). This also includes the full text of ‘Two Concepts of Liberty’. The best commentary on Berlin's writings is Isaiah Berlin (Fontana, 1995) by John Gray. Although quite difficult in places, this book extracts the main philosophical themes from Berlin's work.