From Telegraph review of Hastings' WW1 book.

However, Hastings's recent massive volumes on his specialist subject, the Second World War, have shown why his position as Britain's leading military historian is now unassailable.

In this enormously impressive new book, Hastings effortlessly masters the complex lead-up to and opening weeks of the First World War. As a historian, his objective is twofold: to pin the principal blame for launching the catastrophic conflict where it rightly belongs: on Austria and Germany; and to argue unashamedly that Britain was right – politically and morally – to fight it.

Hastings's second adversary is more amorphous: what he calls "the poets' view" of the war as a futile struggle for a few blood-drenched yards of mud, which wasted a whole generation, solved nothing and which Britain should have steered clear of, allowing those funny foreign fellows to slaughter each other without compromising its splendid isolation.
This view, propounded by various powerful voices from the great economist John Maynard Keynes in 1919 down to the scriptwriters of the television comedy Blackadder Goes Forth, has been hammered so relentlessly into our heads that it is now the received opinion on the war. So much so that the government seems unsure how to mark next year's centenary of the conflict, both for fear of upsetting the Germans and because British public opinion generally regards it as a senseless, unmitigated tragedy.
Hastings, who received a knighthood in 2002, will have none of this.

Hastings pushes the parallels between the two world wars even closer. He details the barbarities perpetrated by the Kaiser's armies as they marched through Belgium, showing that such atrocities, though smaller in scale than the Nazis' crimes in 1939-45 (6,000 civilians murdered rather than six million), were inflicted in the same wanton spirit. With irrefutable logic Hastings argues that if it was right for Britain to wage war in defence of Poland in 1939, then it was also correct to take up arms in defence of Belgium in 1914.