All Hell Let Loose is a history of WWII, by Max Hastings. One of the children had it; I read it; it wouldn't normally be my reading material. It is a thick book, with some illustrations. I thought it good.
Danger: spoiler alert: the Germans lose.
The main advantage of the book is it's sweep: it covers the entire war, in very rough proportion to the amount of death and fighting, and so covers the Eastern Front far more than the traditional English schoolboy education, that I received, ever did. It also, somewhat refreshingly, largely covers the actual fighting, rather than politics, or causes, or economics. It doesn't entirely ignore economics, of course - pointing out, for example, that pure weight of US industrial capacity doomed Japan from the start (so why did they fight at all? Because they were stupid enough to deceive themselves: they thought they could expand, and then offer peace, which the US would accept though being soft and reluctant to accept casualties).
Other "nice" things it mentions - again, an example from Japan-US - is that some of the land campaigns were strategically pointless. Not all; some tiny rocks captured for airstrips were valuable. But once the US had wound itself up, it's submarines and surface Navy had largely suppressed the Imperial Navy, and so large garrisons of Japanese troops on... the ?Philippines? - I recall the concept, of course, not the actual examples - were no harm to anyone. They could have been bypassed and dealt with after the war was finished. But all the obvious things - commanders who wanted to fight, an army that had been created and therefore had to be used, lack of will in the overall command - meant that a whole pile of mainly US troops would die pointlessly killing lots of Japanese troops.
Slightly to my disappointment he doesn't cover "what if"s much. The most obvious large-scale "what if" is perhaps what if the Germans had put up lesser, or even token resistance on the Western front and diverted resources to the Eastern (of which the "battle of the Bulge" would be only a part). Then the Western allies would have reached Berlin and parts East first, perhaps even in 1944, leading to much less misery for Germany but perhaps also a much altered post-war balance, since the Commies would have got to conquer much less of Eastern Europe. The answer to this is perhaps that Hitler was mad enough to think he was going to win - or felt obliged to claim this in public - and so couldn't adopt this as a policy; that would only have been possible if he'd been deposed by the generals, but in that case they'd probably just have surrendered, so we rapidly go off into "actually, it couldn't have been like that".
There are hints of other "what if"s: he suggests that the Africa campaigns were but a side-show and largely pointless; but also that better strategy from the Krauts might have cleared the British out of the Med entirely, in which case Egypt and so on might have gone rather differently.
Philip Hensher writes a review that promotes the "individual voices" in the book. And, true, Hastings does quote quite a few people, officers, men, and civilians. But I wouldn't count that as a major part of the book.
Another good bit of myth-busting (again, to this English ex-schoolboy) is how poorly our armies performed in the colonies in the Far East against Japan. There's a certain myth that though there were a fair number of blimps in charge the actual fighting men were good; but this doesn't really seem to have been true. Few of the British soldiers particularly believed in what they were doing, and so weren't good at it.
And, so it goes. Overall, he does a good jobs of grinding in the terrible destruction wreaked on hapless populations by the fighting going on over their heads, largely in the Eastern Front. And all so totally pointless.