The great men of power who seek to change the nations they belong to usually are pretty terrible people.

The Second World War is the largest single event in human history, fought across six of the world's seven continents and all it oceans. It killed 50 million human beings, left hundreds of millions of others wounded in mind or body and materially devastated much of the heartland of civilization.

Even a pacifist should admire the military virtues.

We saw the children and the women with their babies and then I heard the poouff — the flame had broken through the thatched roof and there was a yellow- brown smoke column going up into the air. It didn't hit me all that much then, but when I think of it now — I slaughtered those people. I murdered them.

Of whatever class or nation, however, all successful participants in the repetitive and unrelenting stress of aerial fighting came eventually to display its characteristic physiognomy: skeletal hands, sharpened noses, tight-drawn cheek bones, the bared teeth of a rictus smile and the fixed, narrowed gaze of men in a state of controlled fear.

Men killing other men really is an extraordinary phenomenon. Why does it happen? And how long has it gone on? And have the motives changed?

The revival of Islam dates from the early years of the 20th century. It was brought about by their humiliation, by their sense of how low they'd fallen compared with the West.