I'm not a big reader of science fiction, but when I saw in this morning's Times that Stanislaw Lem had died, I counted 17 of his books in my bookcase, mostly purchased over 20 years ago.
The first Lem I read must have been Solaris (1961), because I had seen the movie in the mid-70s and was intrigued by the premise and ideas. Several others of his books have stuck in my head more than that one, however.
I remember the long opening section of Return from the Stars (1961) in which space explorers have returned to Earth after many years and can't seem to find their way out of the space port. All of the information systems are working fine, but of course they make reference to foreign objects and concepts. The people on Earth are now given drugs to curb their violence. It leads to worldwide peace, but also to a lack of adverture and curiosity.
Lem could be very funny as well. I remember collapsing nearly in tears from reading "The Seventh Voyage" from The Star Diaries (1971) in which space explorer Ijon Tichy encounters a kind of time warp in which he has to deal with versions of himself from different days of the week, all of whom insist on fighting with each other.
And I remember Fiasco (1986), which I read when it was first published in the U.S. in 1987. Explorers from Earth try to make contact with another planet whose people don't wish to respond. Through misunderstanding and flawed logic, the standoff escalates to catastrophic proportions.
This is the one I've pulled out to read again.