Michael Ignatieff met Isaiah Berlin in 1987. Berlin was almost eighty. He hadn’t written an autobiography, and it didn’t seem that he was looking for someone to write his life story.

From 1987 Ignatieff visited Berlin regularly, at both his flat in Piccadilly and his home outside Oxford, to interview him about his life. In due course these interviews became the basis for a biography. What is immediately striking about Ignatieff’s book, and his interviews with Berlin for BBC2 in the 1990s, is not just that Berlin was a great talker but that Ignatieff was a superb listener, picking up on key details and gaps. He was interested in Berlin’s ideas, of course, but above all this is the telling of the story of a life: from Berlin’s early childhood in Riga and Petrograd, where he witnessed both Russian revolutions; to the pre-war Oxford of AJ Ayer, Stephen Spender and Maurice Bowra, wartime Washington and then fame at Oxford in the 1950s and ‘60s.

There are accounts of the great people he met: political leaders like Churchill, JFK and Weizmann; cultural figures like Anna Akhmatova, Stravinsky and Boris Pasternak (Berlin was one of the first people to read the manuscript of Doctor Zhivago); Virginia Woolf and Freud; Shostakovich and Keynes; the spies Burgess and Maclean. “There was the great Isaiah Berlin,” wrote Woolf after they met at Oxford, “a Portuguese Jew by the look of him, Oxford’s leading light; a communist, I think, a fire eater … ” A few years later the young Berlin visited Freud. “When tea was over,” Ignatieff writes, “Berlin departed, feeling that he had spent an hour in the company not of a genius, but of an old Jewish doctor, clever, malicious and wise.”

There are also the great events that made Berlin’s reputation: reporting on American public opinion during the Second World War, visiting Moscow and Leningrad at the height of Stalinism. He was at the Kennedy White House at the time of the Cuban Missile Crisis; meeting with Weizmann and Ben-Gurion to discuss the possibility of a Jewish state and, later, discussing whether Berlin might serve in the new state of Israel. Perhaps most importantly, there are the ideas of the greatest thinkers and political philosophers of the 20th century, people whom he respected like JL Austin, Raymond Aron and Wittgenstein; and those he despised, like Hannah Arendt.

This biography is such a fascinating read because Ignatieff is interested in Berlin the man as well as the thinker. Why does Berlin have so many “periodic collapses” at crucial moments? When he became the first Jew ever elected to All Souls, and only the third Jew ever elected as a fellow of an Oxford college, he “fell ill for two months from sheer nervous release”. Later, when a woman he loved broke off their relations, “[f]or two days Isaiah was prostrated, unable to get out of bed”.

Ignatieff is particularly good on what Berlin’s Jewishness meant to him. What was it like to be a foreigner and an outsider at Oxford, especially in the 1920s and ‘30s, or when he had to deal with the Foreign Office during the war? A Foreign Office memo “described the author [of a report] as a ‘Mr. Berlin, of Baltic Jewish extraction, by profession a philosopher’”. Churchill wrote to Anthony Eden that Berlin’s summaries “present a somewhat perfervid picture of American affairs”. Eden replied, “There is perhaps a too generous Oriental flavour.” The language tells us a lot about British attitudes towards Jews at the time.

Ignatieff writes about the fate of Berlin’s relatives murdered in the Holocaust, shot in the woods outside Riga. Why, he asks, did Berlin not “write directly about the Holocaust in his later work”? “It was Stalin’s crimes, not Hitler’s, that roused his most intense imaginative response.”

The two chapters on Berlin’s visits to Moscow and Leningrad just after the war are superbly written. It was not long after the Yezhovshchina, “the wholesale extermination of the Russian intelligentsia in 1937”. “By the time the killing and deportation were done, there was a vacant stillness in Russian culture, like a forest after an all-consuming fire.” Ignatieff goes on, “As Isaiah was later to observe, those who had survived were like Giotto’s fresco of Jonah in the jaws of Leviathan, half swallowed by the whale.”

Ignatieff details the three strands in his life — Russian, English and Jewish

Berlin’s encounters with Boris Pasternak and then with Anna Akhmatova changed his life. In a letter written soon after his return, Berlin described his meeting with Akhmatova as “the most thrilling thing that has ever, I think, happened to me”. “Berlin,” writes Ignatieff, “was the rarest of visitors from the lost world of Europe: a native Russian speaker who felt … that the culture of the nineteenth century was his spiritual home.” From then on, figures like Herzen and Turgenev became hugely important to Berlin. When he sought to define his political values as a liberal philosopher, he thought of the pre-revolutionary intelligentsia that had been brutally destroyed by Stalinism.

Towards the end of his biography, Ignatieff writes about Berlin’s speech when he accepted the Jerusalem Prize in 1979, detailing the three strands in his life — Russian, English and Jewish: “From the Russian thinkers, his beloved Herzen and Turgenev, he had taken his fascination with ideas … From the British side, he took his empiricism … but he also ascribed to the English the entire content of his political beliefs: toleration, free discussion, respect for the opinion of others. As for the third and final strand, he told his audience that he owed to Judaism the fact that his liberalism had given such room to the human need to belong … Belonging was more than possession of land and statehood, it was the condition of being understood itself.”

Ignatieff has done an excellent job of slicing the cake, making room for Berlin the liberal political philosopher and historian of ideas, but also for the man, a sparkling conversationalist, a devoted friend, a gossip, an outsider who became a consummate insider, sometimes courageous, sometimes liable to sit on the fence.

The writing is first-rate. Early on, Ignatieff describes their encounters in Berlin’s flat in Albany. Most of his life, he writes, “has been spent in places just like this, in the walled gardens and high-windowed rooms of English institutional privilege”. He later describes Berlin’s first night in England. “After breakfast, Isaiah got up, went over to the piano in the sitting room and with one hand, picked out ‘God Save the King’.” “His was a version of Englishness frozen in the moment when he first encountered it in the 1920s,” Ignatieff writes, “the England of Kipling, King George, G.K. Chesterton, the gold standard, empire and victory.”

These are the familiar virtues of the original 1998 edition of Ignatieff’s biography, which was published just after Berlin died. Two things have happened between that edition and the new second edition published by Pushkin Press, however. First, four volumes of Berlin’s letters have come out, superbly edited by Henry Hardy and his colleagues, and Hardy has produced further definitive editions of Berlin’s work. Second, Hardy, Berlin’s literary editor for many years, has added numerous footnotes and corrected errors from the first book. “This biography,” writes Ignatieff, “now stands on the secure foundations of his exemplary editorial work.” It is an admirable collaboration: Ignatieff’s empathy and insights; Henry Hardy’s “fastidious commitment to accuracy”; and, of course, above all, Isaiah Berlin, one of the great British intellectuals of the 20th century, who lived an extraordinary life.