Mark Mazower is a distinguished historian of 20th- century Europe, best known for his work on Nazi occupation policy in the Balkans and in Eastern Europe. Educated at Oxford, he is now a professor at Columbia University. What You Did Not Tell — subtitled A Russian Past and the Journey Home — is the saga of his family’s Russian origins. Its central theme is deracination, the strains it imposes on the psyche, and how successive generations of Jews have coped with it.

Mazower’s grandparents had uprooted themselves from Russia and his father grew up in placid surroundings in North London. Reticent about the family background, it was only during his last illness that Mark was able to talk to him about his roots. Mark’s grandfather and many other family members had been Russian socialists, though not Communists, at a time when socialism seemed the wave of the future and Zionism an aberration.

Most had supported the Bund, a secular Jewish socialist party, part of the Social Democratic party in the Tsarist empire. Though largely forgotten today, at the beginning of the 20th century it had more members than either the Bolsheviks or the Mensheviks, both much smaller groupings then than they were later to become.

The Bolsheviks had little time for the Bund, since they thought in terms of class, not ethnicity. Lenin is said to have referred to Bundists as Zionists suffering from sea-sickness. Nevertheless, the Bund supported the Soviets in 1917, but dissolved itself in 1921. Many of its members were to perish in the 1930s during Stalin’s purges. Mark’s grandparents, who emigrated, were among the lucky ones.

In the 1990s, a school friend of Mark’s father, the distinguished Israeli historian, David Vital, came to dinner with them in Highgate. Vital spoke of his father’s respect and admiration for Jabotinsky, leader of the Revisionist Zionist movement. One of the guests began “one of the last rounds in an argument that had begun around 1900”, by musing: “Jabotinsky? Wasn’t he like Hitler?”

But the Zionists had won the argument. They had won what Mazower calls their wager on fate; and the Bundists would have fared better if they had been able to overcome their sea-sickness.

But his book is not primarily about politics. It is an inquiry into the importance of roots and the psychic contentment that comes with belonging. Confidence, Mazower believes, “comes only from knowing where you are from”, and his parents were privileged, “in being able to stay put, in choosing when to move”.

Indeed, they saw themselves not as immigrants, assimilating into an undifferentiated British culture, but as representatives in Britain of a Russian-Jewish intelligentsia, now sadly dying out. It was this dual identity — as Russian-Jewish and as British — which gave them psychological stability.

What You Did Not Tell is a marvellous book from the pen of a fine historian, written in a foreign country and steeped in nostalgia.

What You Did Not Tell: A Russian Past and the Journey Home

Vernon Bogdanor is Professor of Government at King’s College, London.