Alan Brooke was the most hyphenated of Irishmen. He was of famous Ulster stock, spent his childhood mostly in France, and though Ireland was no doubt a pleasant place for him to visit with all its big houses and securely Protestant lawns and laws, it is unlikely that its common people had any formative influence on him at all. To be frank, it is barely relevant. Alanbrooke - his final, lordly title - rises above nation or nationality. As these diaries make plain, he is one of the most morally heroic figures of the second World War. Ulster may claim him, but he belongs to the world.
He was a great soldier - decisive, modest, clear-minded, hard-working and honest - and to him must go much of the credit for the brilliant withdrawal from Dunkirk.
His courage was shown in his unflinching resistance to Churchill's readiness to sacrifice the 52nd Lowland Division in 1940, as he had already squandered the gallant 51st, in a gesture of witless futility to make the French feel the British were supporting them. "I replied that it was impossible to make a corpse feel, and that the French army was, to all extents and purposes, dead, and incapable of registering what had been done for it," wrote Alanbrooke.
His thanks was a typical response to criticism which Churchill had forged in the Boer War and hardened at the fiasco of Gallipoli: this was to accuse Alanbrooke of "cold feet". It is a bully's way of making a soldier subject to a lesser mind; and in so many ways, Churchill's was an infinitely lesser mind than Alanbrooke's.
In one sense it comes to morality. Somewhere in his gallicised childhood, Alanbrooke had osmotically absorbed those fundamentalist Ulster Protestant notions of personal frugality and individual honesty. It was these qualities, plus an astonishing capacity for hard work, which made him such an outstanding Chief of the Imperial General Staff for much of the war. These, plus an integrity of almost shocking inviolability, caused him to turn down command of the Eighth Army in 1942, because by then he knew that he alone could control the crazy and wanton impulsiveness of the one man who could lose the war, but certainly could not win it: Winston Churchill.
This is soldierly modesty at its greatest, for soldiers take commissions with their hearts set on field command. To have turned down that glittering prospect, with certain victory and all its glorious fruits beyond - how mouth-watering in retirement must the un-on title, Alanbrooke of El Alamein have seemed - for the sake of a greater cause, is proof of a great man; in Alanbrooke's case, as it happens, a very great man indeed. Without the magisterial presence and soldierly wisdom at Churchill's shoulder when he was dead set on lunatic folly at every turn, the outcome of the second World War could have been quite different.
As it was, Churchill's dark moods, his mad impetuosity, and his almost irresistible desire to interfere in matters he knew almost nothing about were constant perils.
In its most extravagant form, his whimsy turned what would have been a swiftly victorious middle-eastern campaign of 1941 into a series of calamitous defeats that took two years, and many thousands of lives, to rectify.
At times Churchill was seriously unhinged, and on his journey to Quebec on the Queen Mary in September 1944, quite off his trolley. Alanbrooke's account of rambling paranoia foreshadows perfectly The Ordeal of Gilbert Pinfold. Yet there can be no denying that Churchill's ferocious willpower was a decisive factor in the defeat of Naziism.
His almost Celtic qualities of intuition and inspiration combined well with Alanbrooke's rather more Anglo-Saxon, Protestant and reliably empirical mind: ying and yang in a common contest to restore the rule of law and of civilisation to Europe and the greater world.
The two men worked unconscionable hours, Winston drinking brandy when other men take breakfast, Alan inspecting troops, restoring morale, and mediating between warring generals. In a single year, he flew 14,000 miles in ancient aeroplanes without navigational aids and drove 70,000 miles in the blackout along the ancient stagecoach and cattledrovers' tracks of Britain - and this in his 60s , with all his other huge duties to attend to.
Alas, rubbish rises. In retirement, this good and worthy man was obliged to sell his diaries both to stay alive and to counter the meretricious and self-serving memoirs that were bubbling from his lessers.
The much bowdlerised version of his diaries caused uproar at the time - but alas, the deletions of their editor, Arthur Bryant meant that many justified targets escaped stricture - such as the truly abominable Louis Mountbatten, a conceited, vainglorious, shallow and ruthless popinjay.
The Alanbrooke Diaries chart a deeply troubled journey by a deeply moral man through the confusion and indecision of high command at the most difficult time in world history. Some of his peers emerge through the fog and clutter of history as good men, others as lesser, more greedy creatures.
Alanbrooke stands almost alone at the head of the heap, a great man who forswore greatness that a greater greatness might be done to mankind.
This is a most marvellous book, one that finally honours a man who helped save European civilisation, and whom we should be proud to call Irish - if only, sort of.
Kevin Myers is a columnist with The Irish Times. His novel, Banks of Green Willow, is being published in the autumn.