It having been the world-historical episode which shaped the world I grew up in, a war which involved all senior members of the family, I have read scores of books about the second world war. In the past Shirer's Rise and Fall of the Third Reich was the book I'd recommend to younger people interested in the Western theatres. Now, however, I'd recommend Ponting's Armageddon. Shirer's book is still worth the effort, but it is long, very detailed and very close to the events it describes. Pointing writes from a greater distance, covering all theatres with a thematic approach.
What comes across from this study is how amorally self-interested governments are. None come across as noble or honest. The most one can say is that some stood up for some of their citizens occasionally. Otherwise, while Nazi Germany still holds the record for intentional, industrialized genocide and murder, the moral gulf between them and "us", the Allied powers, is very narrow in this study.
Although I knew, being Norwegian myself, that the U.K. had violated Norwegian neutrality twice before Germany preemptively and reluctantly invaded it and Denmark, I had not known that the U.S.A. had invaded Iceland, then Greenland, over Danish protests. Nor had I known that we went on to grant Iceland independence in 1944, again without consulting the Danes. Although I knew that the war with the U.S.S.R. was bloodiest, I was staggered to learn that until 1944 and the Battle of the Bulge, over 90% of Germany military strength had been on the eastern front--the war in the west being a virtual sideshow.
As might be expected from any serious study of the war, economic factors are emphasized. That Germany and Japan--and the U.S.A. and the U.S.S.R. for that matter--aggressed was virtually inevitable, given their economic interests and capacities and given the reluctance of declining powers such as China, the U.K., the Dutch and the French to give up the benefits accrued during their own, earlier periods of growth.
What's lacking in this relatively short book is any analysis of class and class interests. A broad division is made, naturally, between the politicians who made the decisions and the citizens who suffered the consequences, but the usually enormous divide between their interests, while demonstrated repeatedly during and after the war, is not examined.