It is not often that a single map can illuminate the subject of a book, but the hideous array of concentration and extermination camps depicted in Michael Burleigh’s history of the Second World War reveals at once the genocidal aspect of Hitler’s regime.

Moral Combat (Harper Press, £30) is an exceptional book, far removed from the grand strategy and the battlegrounds at the heart of most current war literature. This is not to downplay the electrifying consequences of individual actions. Burleigh’s focus is the moral element — right or wrong, kill or be killed — that confronts the soldier, sailor or airman in the heat of campaign. Centre stage are Hitler and Hirohito, Stalin and Mussolini in this analysis of infamy in war.

The moral peak of this book, perhaps inevitably, is the bombing raids over Germany when thousands of innocent civilians were slaughtered as the giant fortresses made their way to Berlin, Hamburg and Dresden in a “pyrotechnic blizzard of pink, white and orange explosions”.

Does this constitute atrocity? The controversy rages on, but compare it with the massacre of inhabitants of Lidice in reprisal for the assassination by Czech agents of the brutal Reinhard Heydrich, or the extermation of the Jews at Auschwitz or Treblinka and we may get nearer to the genocidal truth.

“Nuremberg established that offences committed in the heat of battle could not be considered in the same light as cold-blooded crimes against humanity,” declares Burleigh.

In one of many individual stories that crisscross this penetrating work of art, he refers to an American infantryman who comes face to face with an honest-looking Japanese soldier in Bataan, famous for its death march. He has no means to take him prisoner and is faced with a life-and-death decision. He shoots him dead and his conscience haunts him until his friend tells him simply that it is wartime. Moral Combat raises such intolerable questions.