The Future According to Stanisław Lem
I think Lem wrote sci-fi just by coincidence. Soviets would not allow any sort of criticism on serious stuff. But they adored sci-fi and cosmic future of mankind. Lem could write undisturbed on this field.Western sci-fi authors such as Asimov and Clarke were great, but they were not best what literature can offer. In many cases they use story as boilerplate to present some technical marvel. Lem was one of the best authors, even outside sci-fi.