Churchill examines in detail the mistakes that led to the war in Europe. The outlines of these errors are known to most people who have even a cursory knowledge of the period, but by reading Churchill's own personal account, we can see the subtleties and ambiguities of decisions made by world leaders in great detail. The failure of Britain and France to stand up to Hitler during a long chain of events in the 1930s was, Churchill asserts, a fatal mistake. That said, Churchill gives credit where it is due to Chamberlain's decision to finally draw the line and declare war upon Hitler's invasion of Poland. A lesser-known detail is that, prior to the Molotov–Ribbentrop Pact between the Soviets and Germans, overtures had been made that could have established a Triple Alliance among Russia, Britain, and France. That this was not accomplished, Churchill correctly states, was a tragic mistake, given that Hitler took action in invading Poland in conjunction with Stalin's simultaneous invasion from the east.

Churchill justly and repeatedly gives credit to his countrymen for their famously indomitable spirit, their refusal to give up, and their solidarity in the face of the possibility of invasion. The political situation of the time is a more complex matter, but the same principle is relevant in the formation of the National Coalition when Churchill replaced Chamberlain as prime minister in 1940. Churchill makes it clear that he himself refused to point fingers at either Conservative or Labour members of Parliament over the mistakes made in the period prior to war. Popular history has seen Neville Chamberlain as the sole culprit in the appeasement of Hitler, but other factors were involved. As Churchill relates,

Here was this people [the British], who in the years before the war had gone to the extreme bounds of pacifism and improvidence, who had indulged in the sport of party politics, had advanced lightheartedly into the centre of European affairs, now confronted with the reckoning alike of their virtuous impulses and neglectful arrangements. They were not even dismayed. They defied the conquerors of Europe. They seemed willing to have their Island reduced to a shambles rather give in.

Here, Churchill pays tribute to his people by realistically describing the complexity of their sometimes contradictory feelings but concluding with the fact of their resolution not to yield to defeat.

A frequent theme both here and in other writings by Churchill is that of the basic solidarity of all English-speaking peoples. His personal connection with, and his admiration for, President Roosevelt are evident throughout his narrative of the war years. Churchill acknowledges the aid given to Britain by the US and makes no apology for his welcoming the fact that the war was finally brought to America:

No American will think it wrong of me if I proclaim that to have the United States at our side was to me the greatest joy.

Churchill knew that Japan had effectively committed suicide by attacking Pearl Harbor and declaring war on the US. And he had no doubt that US participation in both theaters of war was the key to the defeat of the Axis Powers.

To his credit, Churchill describes his own feelings and does not provide us with any forced "objectivity" or detachment from events. His own pride in his nation is part of this, his flag-waving description of "the buoyant and imperturbable temper of Great Britain, which . . . may well have turned the tide" of war. But in asides, too, we see the man himself, as in his famous anecdote about his habit of taking an hour-long nap every afternoon, which then refreshed him and enabled him to work until two or three o'clock in the morning. It is a small point but a telling one amid the stupendous detail Churchill presents in his account of the largest war in history.