Highly recommend “The Expanse” series of books. Really great story, really great characters, and some moderately heavy topics. Good books to get lost in.
I also recommend CS Lewis’ space trilogy which starts with “Out of the Silent Planet”. Very accessible but well-written sci-fi that’s not nearly as long as other traditional Sci-Fi.
Heinlein is also all wonderful (Starship Troopers is a goodie that’s very different than the movie).
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