The absolutely best modern sci-fi series is F. Paul Wilson’s LaNague Chronicles!! Bar none, IMHO. His first book (first published, as well as the first in the series) Healer is a fantastic introduction to Libertarian philosophy. So subtle, it draws the reader in without you even realise what’s happening.
It’s not the most complex or well-written book I’ve ever read, but still significant.
https://www.amazon.com/Complete-LaNague-Federation-ebook/dp/B00BH2KO2O/ref=sr_1_fkmr0_2?ie=UTF8&qid=1512090190&sr=8-2-fkmr0&keywords=LaNague+Chronicles