Everything About Fiction You Never Wanted to Know.

Written by Larry Niven and Jerry Pournelle, Footfall is a novel describing the arrival of alien space elephants from Alpha Centauri. Set in a very hard universe, they have no choice but to try and take over Earth because they don't have any kind of FTL and spent all of their planet's resources getting here. Humanity objects. Strongly.

Tropes used in Footfall include:
  • America Saves the Day: The military force at the end is American in nature.
  • Blue and Orange Morality: The aliens and humans really don't quite understand each other's psychology, mainly because the aliens have much more of a herd dynamic. Most relevantly, the aliens don't understand how or why you would possibly initiate diplomacy before first fighting to see which party was dominant. Likewise, they don't understand why a battered humanity responds with total war (pretty much an unknown notion to them), rather than taking a Defeat Means Friendship-type submissive relationship.
  • Break Out the Museum Piece: The guns from museum-ship battleships are pulled out of mothballs to fight the fithp, both on the Archangel Michael itself and parasite ships built around each cannon.
  • The Can Kicked Him: A character is killed by holding his face in a toilet until he drowns.
  • Colony Drop: "Footfall" involves slamming a large asteroid into a planet.
  • Creative Sterility: The fithp don't research or develop new technology, they get it from their Precursor artifact.
  • Death From Above: First, the fithp use space-based lasers and the 'Rods From God', orbital kinetic kill weapons, to destroy Earth's military forces and insurgents; later, after Kansas is nuked to defeat their first invasion they land the eponymous "Foot" (an asteroid) in the Indian Ocean to try to force Earth's surrender (it doesn't work).
  • Defeat Means Friendship: The fithp figure humanity will either submit to their armies, or accept the submission of their armies, and either way it'll lead to good relations in the long term. They're wrong.
  • Dramatis Personae
  • Generation Ship: The ship the fithp arrive on is a very long range generation ship that operates with a Bussard ramjet.
  • Godzilla Threshold: The first time, they nuke the territory the aliens took over (which was still populated by humans). The second, and significantly less significant time, they build and use a nuke-fueled spaceship. They did get most of the nearby area into bomb shelters before they took off, though.
  • Heroic RROD: During the climactic space battle, construction worker-turned-spacecraft-repairman Harry Reddington stays to fix a leaking steam shunt despite the fact that the steam escaping around him is raising his body's internal temperatures up above the point at which the human brain shuts down. He gets the job done, and manages to die shortly thereafter from exhaustion, just before a leak in his pressure suit would have killed him anyway.
  • Humans Through Alien Eyes: The fithp reflexively remain submissive once they've surrendered to an opponent. They find it difficult to understand beings that will pick themselves up after a defeat and come back for a rematch.
  • Insufficiently Advanced Aliens: If the fithp hadn't had a Precursor artifact handy to tell them how to build stuff, they probably would still have been at the hunter-gatherer stage of civilization.
  • It's Raining Men: A mass paratroop drop by invading aliens who looked like two-trunked elephants flying hang gliders and wearing platform shoes (designed to absorb the landing impact).
  • Kinetic Weapons Are Just Better: The primary weapons of the fithp are described as "crowbars dropped from orbit". For that matter, the personal weapons used by them are just scaled up versions of ordinary machine guns.
  • Language Equals Thought: The fithp language makes extensive use of inherent plurals, for example fithp (which means tribe or group or herd) and fi' (which means a person). This fact reflects a lot about basic fithp psychology.
  • Macross Missile Massacre: During the attack by the fithp, one of the main characters explicitly comments that the barrage of incoming alien missiles reminded him of a Japanese science fiction cartoon.
  • Meaningful Name: Footfall.
  • Most Writers Are Writers: Several sci-fi authors, including clear Author Avatar versions of both authors as well as one of Robert A. Heinlein, brought together by the government to help think up ways to fight an alien invasion.
  • Nuke'Em: The humans build an Orion Drive spaceship named Michael to combat the invading aliens. And since it runs on nuclear bombs, why not bring along nuclear-tipped missiles, nuclear cannon shells, and just for fun, nuclear-pumped x-ray lasers running off of the main drive's wasted energy.
  • Orion Drive: Project Michael, the last ditch effort to win the war, as the fithp hold the orbitals. Whenever the main engine was in operation in the ensuing space battle, the onomatopoeia "WHAM WHAM WHAM WHAM" was used. One of the crew reflected that "God was knocking, and he wanted in bad."
  • Possession Implies Mastery: Subverted. Although the fithp have a great deal of advanced technology, compared to the humans, it turns out that they are a young race who found a cache of technological knowledge left by another, older species and built their entire civilization around it. But they never developed any kind of science and have a cultural tunnel-vision centered around the technologies in the cache; not only are they unable to analyze or extrapolate base principles from the ancient knowledge, but they cannot imagine or cope with a technology not laid out in detail for them in the cache. They know how to use it and that's all they know about it.
  • Precursors: The aliens have them for a change. They left an Ancient Artifact around filled with plans for stuff but little in the way of anything else.
  • Ramscoop: The propulsion sistem for the fithp mothership.
  • Stanley Steamer Spaceship: The spaceship with an Orion-class nuclear engine that is indeed cooled by and powered by steam. At one point one of the characters has to work to repair battle damage in an area made uncomfortably hot by a burst steam line.
  • Ramming Always Works: In the final attack on the alien mothership, the shuttle Atlantis rams it, damaging the alien's main drive, allowing Michael to catch them.
    • This was also explicitly always the final attack option for the Michael, as it was, literally, the last chance for humans to win the war. The crew all signed on with the expectation that they would likely die this way and take the enemy mothership with them.