The strength of Caute's book lies primarily in its interweaving of central ideological issues in the Cold War debate with pertinent biographical details concerning his two chief protagonists. In the case of Deutscher, who first made his name in 1949 as the biographer of Stalin and then of Trotsky (in three volumes), Caute conveys some of the forcefulness of his style, his flamboyant pathos and identification with the Bolsheviks. At the same time, he does not conceal Deutscher's more obvious weaknesses — the overconfident, sweeping generalisations, the false prognostications, imaginative excesses and dogmatic pronouncements-all attributes which Berlin, with his ingrained scepticism, keenly distrusted. Some of the more exasperating features of Deutscher's outlook (aspects which Caute believes aggravated Berlin's antipathy towards him) were manifest in his Marxist contempt for Judaism and the state of Israel. Although Deutscher, in the wake of the Holocaust, had briefly modified some of his pre-war opposition to Zionism, in the 1960s, he once again became a fierce critic. On the eve of his death, in a vitriolic interview in the New Left Review (June 23, 1967) he effectively inaugurated a new era of New Leftist anathemas against the Jewish state. With stunning partiality, he accused the Israelis of "belligerence", arrogance, "fanaticism" and "racial-Talmudic exclusiveness", while virtually ignoring the bloodcurdling threats of Nasser and the Arabs to destroy Israel in the run-up to the Six Day War.

Berlin, on the other hand, was a consistent liberal supporter of the Jewish state, a disciple of the moderate Zionist leader Chaim Weizmann, seeing Israel as indispensable for Jewish survival in the modern world. While privately critical in later life of Likud-oriented Israeli settlement policies, Berlin found Deutscher's harsh judgments on Jewish themes to be as distasteful as those of the increasingly influential German-American Jewish philosopher Hannah Arendt.

Caute's portrait of Isaiah Berlin does not, in itself, break much new ground for those already familiar with Michael Ignatieff's landmark biography or with the publication of Berlin's extensive correspondence in recent years. (The third volume, Building: Letters 1960-1975, has just been published by Chatto & Windus, edited by Henry Hardy and Mark Pottle.) But it does vividly remind us of how antithetical Berlin's core values were to Communism both as an ideology and as a political system. All his life Berlin had fought against the totalitarian cult of certainty, the belief in absolute truths, historical determinism, and intellectual uniformity, vigorously opposing any denial of individual choice, cultural diversity and political pluralism. Yet despite his own liberal individualism, Berlin openly empathised with the need to belong, to be part of a community, to enjoy the sense of a common national consciousness and culture, a feeling of connection with one's ancestors. This may explain Berlin's lifelong fascination with thinkers like Johann Gottfried von Herder or the German Romantics, as well as his preoccupation with the dilemmas of the 19th-century Russian intelligentsia. It also helps to elucidate Berlin's repeated disapproval of any radical assimilationist form of Jewish self-negation, despite his own successful integration into English academic and social life.