Blackout / All Clear - Connie Willis
A science fiction novel that is really a love letter to everyone who won World War II by doing their part. Which, often, consisted of getting up and going to work in spite of the German Air Force doing their best to murder you and everyone you loved.
I do not know how they did it. Before the war, I read elsewhere, the government was convinced that just a few short weeks of that thing and everyone would be dead, fled, or rebelling. But no - they stood up to it for eight months. Nobody special, not soldiers or Spartans, just ... people.
Anyway: love letter, Blitz, V1, V2, Dunkirk, time traveling historians. Who have a problem with time management, and always miss some terrifically important events going on right under their noses.