"Hard to be a God" (Russian: Трудно быть богом, Trudno byt' bogom) is a 1964 science fiction novel by Arkady and Boris Strugatsky, incredibly atmospheric thing, re-read from time to time
"Deathworld 2" (1964, initially titled The Ethical Engineer) by Harry Harrison ,while reading had the feeling that my thoughts and the thoughts of the author coincide in the view on many things.
"Nineteen Eighty-Four", often published as "1984", is a dystopian novel by English author George Orwell ,
"Orphans of the Sky" is a science fiction novel by Robert A. Heinlein - A lot of things to think about