Really surprised to see no mention of H. G. Wells here, so I'm just going to add it : https://en.wikipedia.org/wiki/The_Time_Machine You can get it at project Gutemberg, so no excuse not to read it. Any book by French author Barjavel are also worth reading in my opinion, especially "La Nuit des Temps" / "The Ice People" ( https://en.wikipedia.org/wiki/The_Ice_People_%28Barjavel_nov... (https://en.wikipedia.org/wiki/The_Ice_People_%28Barjavel_novel%29) ) and "Ravage" / "Ashes, Ashes" ( https://en.wikipedia.org/wiki/Ravage_%28novel%29 )
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