J. F. C. Fuller's The Second World War, 1939-1945: a strategical and tactical history
Very interesting guy, Major-General during WWI serving with distinction in His Majesty's Army, celebrated inter-war theorist, friend of Hart and Guderian not to mention close friend and ally of Sir Oswald Mosley and leading member of the British Union of Fascists, even an acquaintance to Hitler, on top of that he was an occultist and one of the earlier western authors on pagan and far-eastern mysticism...but most of all he was a brilliant military theorist and prolific historian. It's unfortunate that the liberal pc crowd dismiss him because of his political ideology, his objectivity and intelligence far surpasses his peers and as a result his insights are magnificent and unique. Some of the best analysis of latter wars, including Vietnam, out there are little more than a plagiarism of Fuller's military theory, a theory developed in the inter-war era at that (he is to military history what Goebbels is to rhetoric, the Master that everyone reads, and every aspires towards, but no one will admit to).
I'm about half way through this book and I've already come to the conclusion that an understanding of the principles presented is essential to being capable of competently discussing the second world war...it certainly forced me to re-evaluate many deeply held convictions about the war that simply wern't true.