I enjoyed James P Hogans The Proteus Operation. This is an alternate history time travel novel, wherein under this universes natural timeline, WWI really was the war to end all wars, and the entire planet was a global utopian society by 2020. Imagine full globalization but getting only the good parts of globalization. Then some greedy jerks went back in time so that they could be the elites they thought they had a right to be. They helped the Nazis, who won WWII hard(and being Nazis, blew up the time portal the instant they got the nukes so that they didn’t have to share power). Australia, some of the surrounding archipelagos, and North and South America were left. Hitler took the rest of the world, and in 1975 President John F Kennedy was facing a final showdown that the remaining free nations were sure to lose. HE found out about what happened with the time traveling assholes, and started a crash program to send his own time travelers back to repair, or at least mitigate, the damage. It’s interesting how things end.
So I’m checking out another of his novels, Echoes of an Alien Sky. This one is about Venusians visiting Earth long after humanity has gone extinct, and the Venusians investigating possible connections between their people and the people of Earth.