Shaara's book is the story of the Revolutionary war: the battles, the dithering Congress, the intransigent King George, the privation of the soldiers, the evolving strategy of the continental army and allied state militias. Generals Washington, Knox, Greene, Lafayette and others versus Howe, Clinton, Cornwallis, and Benedict Arnold. It's a novel, but Shaara intends the details to be accurate and authentic, with only historic detail manufactured to smooth the narrative. I was 'taught' about the war when I was in middle school, a useless exercise in memorizing locations and dates of battles. Here is what actually happened, the surprises, the mistakes, the arrogance of the well-trained and experienced British.
War never changes, except in the minutia. Washington's successes are similar to victories by WWII commanders: Guderian in 1940 France and 1941 Ukraine, Rommel in 1941 Libya, Patton in 1944 France. The general theme of the British defeat echoes other wars fought to subjugate a population fighting for their independence: Vietnam, Afghanistan, Iraq, and now Ukraine. It is an obvious lesson that each generation of military leaders ignores: an army can't succeed against a united populace; at best, it can defeat the organized, visible enemy and then spend decades of occupation suppressing rebellions. The victory by Washington and the French at Yorktown is perfectly replayed, albeit with 100 times the brutality, at Stalingrad in 1942-43. Von Paulus's 6th army in Stalingrad, like Cornwallis's force at Yorktown, hold their position while their commanders promise relief and reinforcements that they can't or won't deliver. Both battles mark the point where the aggressor becomes the vanquished.