In 1941, at the beginning of the Nazi occupation of Belarus in eastern Poland, citizens were informed that “generosity toward Jews is to be stopped immediately." This policy could have come as no surprise to the Jews of the region, who had been oppressed in various nasty, non-systematic ways as long as anyone could remember. What was a shock, a shock seemingly without end or boundary, was the way in which this policy would be carried out. By the end of the war, only hundreds of Jews remained where once thousands had co-existed, relatively peaceably, in the agricultural communities bordering the forest.

The Bielski family were millers, successful farmers and entrepreneurs. The handsome brothers - Tuvis, Zus and Aasel - cut a wide swathe among the girls of the area, including Gentiles. They brooked no insult, often threatening or perpetrating violence on those who would mock them or try to cheat them for their Jewishness.

In the course of the German occupation, the brothers were to lose their parents and siblings to the cruelty of the Nazis, which began with the creation of ghettos and led on to mass slaughters such as one in which 5,500 people were herded to the outskirts of Lida and machine-gunned into large trenches. There were three trenches for children. Nazi commanders were observed shooting children with their pistols.

The surviving Bielskis became the de facto leaders of a resistance movement that started when they were forced to flee their home. But there was more to it than that. They were all men of incredible will and personal strength who were born to lead others. They insisted on absolute obedience from anyone who wanted to join them, and their credo became not merely to resist, but to save lives. What point could there be in resistance if they left any Jew behind?

They urged family and then strangers to escape the ghettoes and join them in the forest. Those who answered the call were the fortunate few – in all about 1,200 – who survived, despite harsh weather and a state of continual vigilance and warfare. The resistors joined forces, not always completely amicably, with the Soviets who were attempting to regain the territory and who had, or claimed to have, a humanitarian tolerance for Jews.

Konstantin Koslovsky is the only non-Jew who consistently aided the Bielskis. He was rewarded posthumously with the status of Righteous Gentile for hiding, protecting and feeding hundreds of Jews at his home on the edge of the forest.

The book is frank and bloody – it’s hard to read about the excesses of the Nazis, almost at times hard to believe that such things could ever have happened. There is an inspirational denouement: two of the three brothers emigrated first to Israel and then to New York and lived to a fine old age.