I’m rapidly going through the World War tetrology by Hartry Turtledove. I stumbled across the set in a used bookstore, and can’t believe I never heard of them before, aor that they got so little publicity. I’ve never seen them in any other bookstore.
The essence of the story is that Aliens invade the Earth in the middle of World War II. This forces all the nations to put aside their differences and unite against the aliens. Normally books about people taking on aa technologically superior alien enemy are very unconvincing (the movie Independence Day is one of the worst of this type), but in this case Turtledove makes it believable (The aliens are extremely conservative in all things, including technologica change, and they’re using circa human year 2000 weapons of war. They expected humans to still be using circa 1400 technology (which is when their spy probes sent back images), and are not ready for such advanced technology as the humans have. Their IR imaging, radar, and computer-controlled weapons beat the humans’ capabilities hjollow, but they can’t be replaced, whereas the humans still have factories going. The aliens are appalled that humans are on the verge of getting nukes.
Very well done ideas, made even better by Turtledoves’ convincingly integrating historical characters into the story.