More like Three Complete Novels

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The Gods ThemselvesNovel
Isaac Asimovstandalone novel1972
Hard science fiction, set in parallel universe and other star systems.
ThistledownSeries
series5 books1978
completed
Hard science fiction, about space exploration.
Start with The Wind from a Burning Woman →
MacroscopeNovel
Piers Anthonystandalone novel1969
Science fiction, about aliens, set in far future and space.
Starship TroopersNovel
Robert A. Heinleinstandalone novel1959
Military science fiction, about war and coming of age, set in other star systems.
EmbassytownNovel
China Miévillestandalone novel2011
First contact, about space colonization and identity, set in other star systems.
“In the far future, humans have colonized a distant planet, home to the enigmatic Ariekei, sentient beings famed for a language unique in the universe, one that only a few altered human ambassadors can speak.”
from the catalogue
Babel-17Novel
Samuel R. Delanystandalone novel1966
About identity.
“Through Rydra's effort to understand and revise it, the novel explores communication, perception, identity, and translation.”
from the catalogue