was thirty he was at the heart of British intellectual life. He has remained its commanding presence ever since, and few would dispute that he is Britain's greatest living thinker. His reputation extends worldwide - as a great conversationalist, intellectual historian, and man of letters. He has been called the century's most inspired reader.

Yet Berlin's contributions to thought - in particular to moral and political philosophy, and to liberal theory - are little understood, and surprisingly neglected by the academic world. In this book, they are shown to be animated by a single, powerful, subversive idea: value-pluralism, which affirms the reality of a deep conflict between ultimate human values which reason cannot resolve. Though bracingly clear-headed, humane, and realist, Berlin's value-pluralism runs against the dominant Western traditions, secular and religious, which avow an ultimate harmony of values. It supports a highly distinctive restatement of liberalism in Berlin's work - an agonistic liberalism, which is founded not on rational choice but on the radical choices we make when faced with intractable dilemmas.

It is this new statement of liberalism, the central subject of John Gray's lively and lucid book, which gives the liberal intellectual tradition a new lease on life, a new source of light, and which comprises Berlin's central and enduring legacy.