Jack, Jon and Sam Green remember their childhoods as happy and their father, Boris, as a vital part of that. But he was “not an open book at all”. This was surely the same experience as many children of Holocaust survivors. Boris and his brother Fima, who spent years as partisan fighters in eastern Europe, hunting Nazis in the Lithuanian forests, were the only members of their extended family still alive by the end of the second world war. When Fima found Boris again, he was living 200 miles away from their home town with a handful of other survivors,...