'People are my landscape', Isaiah Berlin liked to say, and nowhere is the truth of this observation more evident than in his letters. He is a fascinated watcher of human beings in all their variety, and revels in describing them to his many correspondents. His letters combine ironic social comedy and a passionate concern for individual freedom. His interpretation of political events, historical and contemporary, and his views on how life should be lived, are always grounded in the personal, and his fiercest condemnation is reserved for purveyors of grand abstract theories that ignore what people are really like.

This second volume of Berlin's letters takes up the story when, after war service in the United States, he returns to life as an Oxford don. Against the background of post-war austerity, the letters chart years of academic frustration and self-doubt, the intellectual explosion when he moves from philosophy to the history of ideas, his growing national fame as broadcaster and lecturer, the publication of some of his best-known works, his election to a professorship, and his reaction to knighthood.

These are the years, too, of momentous developments in his private life: the bachelor don's loss of sexual innocence, the emotional turmoil of his father's death, his courtship of a married woman and transformation into husband and stepfather. Above all, these revealing letters vividly display Berlin's effervescent personality - often infuriating, but always irresistible.

Isaiah Berlin was born in Riga, now capital of Latvia, in 1909. When he was six, his family moved to Russia, and in Petrograd in 1917 Berlin witnessed both Revolutions - Social Democratic and Bolshevik. In 1921 he and his parents emigrated to England, where he was educated at St Paul's School, London, and Corpus Christi College, Oxford. Apart from his war service in New York, Washington, Moscow and Leningrad, he remained at Oxford thereafter - as a Fellow of All Souls, then of New College, as Chichele Professor of Social and Political Theory, and as founding President of Wolfson College. He also held the Presidency of the British Academy.

His published work includesKarl Marx, Russian Thinkers, Concepts and Categories, Against the Current, Personal Impressions, The Sense of Reality, The Proper Study of Mankind, The Roots of Romanticism, The Power of Ideas, Three Critics of the Enlightenment, Freedom and Its Betrayal, Liberty, The Soviet MindandPolitical Ideas in the Romantic Age. As an exponent of the history of ideas he was awarded the Erasmus, Lippincott and Agnelli Prizes; he also received the Jerusalem Prize for his lifelong defence of civil liberties. He died in 1997.