General 42 FICTION 41 Science Fiction 17 Science fiction 6 Utopias 6 Exploration sous-marine 5 LITERARY CRITICISM 5 Life on other planets 5 Scientists 5 Sous-marins 5 Submarines (Ships) 5 Time travel 5 Underwater exploration 5 Voyages around the world 5 Voyages autour du monde 5 Core 4 Interplanetary voyages 4 Nuclear warfare 4 Utopies 4 Action & Adventure 3 American 3 Ballooning 3 Civilization, Subterranean 3 English 3 Extraterrestrial beings 3 Guerre nucléaire 3 Hot air balloons 3 Human experimentation in medicine 3 Languages & Literatures 3 Monsters 3