This is a marvellous book, in which Dan Jacobson (whom I have met a couple of times) deals with a lost world.
The Heshel of the title was his grandfather, who died long before he was born: Heshel Melamed, the rabbi of the small, impoverished shtetl of Varniai in Lithuania, then part of the Russian Empire. There was a very large Jewish population in Lithuania, and Vilnius, the capital, where a quarter of the citizens were Jewish, was nicknamed "the Jerusalem of the north" because of its learned rabbis. Faced with increasing persecution by the Tsarist authorities in the decades before the First World War, many Jews were driven to emigrate. Heshel visited the United States in 1912, but despite being offered a position in Cleveland, decided to remain at home in Lithuania. He was alarmed to observe that Jews who emigrated tended to abandon the orthodox traditions of Jewry; and orthodoxy was the whole core of Heshel's being: he despised in equal measure both the Hasidim and the Zionists for departing from its tenets. But when Heshel died in 1919 his family emigrated to South Africa, where they had relatives, thus escaping the horrors that were to come.
In the second part of the book, Jacobson and his son visit Lithuania, now an independent country after the collapse of the Soviet Union, searching for the family's roots. But there is nothing left. Over ninety per cent of Lithuania's Jews were either slaughtered in their villages by the Einsatzgruppen in the summer and autumn of 1941, or transported to the old fort at Kaunus to be shot there. The ninety-six synagogues of Vilnius have dwindled to just one. In Varniai they find only two Jews, both elderly ladies, and an overgrown Jewish cemetery where no-one had been buried since May 1941. A whole civilisation, his grandfather's world, has vanished completely, and, as Heshel had feared, his family, scattered abroad, has abandoned the orthodox Jewish traditions. Jacobson wonders why Heshel had attached so much importance to rigid orthodoxy: what was he being orthodox for? He does not find an answer.