My favorite books for enjoyment are the LOTR series by J.R.R. Tolkien.
My favorite nonfiction is A People's History of the United States from 1492 to Present by Howard Zinn. I can't say I enjoyed the read but the information is transformative.
An absolute recommend when it comes to retro Soviet sci-fi and double that for anyone who has played a S.T.A.L.K.E.R game and enjoyed the setting and concept.