I love just about every one of Robert A. Heinlein's juvenile science fiction novels [1] and still love them as an adult. When I was a teenager, Time for the Stars [2] was probably my favorite, but as an adult, I've come to appreciate Citizen of the Galaxy [3] more. [1] https://en.wikipedia.org/wiki/Heinlein_juveniles [2] https://en.wikipedia.org/wiki/Time_for_the_Stars [3] https://en.wikipedia.org/wiki/Citizen_of_the_Galaxy
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