According to this post at Desbladet (and if you can’t trust Desbladet, what Angloscandiwegian prinsessor-obsessed scandal sheet can you trust?), Stanislaw Lem’s novels have been translated into English pretty much exclusively via French versions. Furthermore, Faber & Faber likes it that way:
Solaris indeed has never been translated directly into English and Mr Lem is dissatisfied with the current translation. Whether this state of affairs will change remains an open question. The following quote from a letter from the Managing Director of the Publishing House Faber and Faber serves as an explanation: “With regard to Solaris, I am afraid that we would not currently be willing either to publish a new translation or to license one.”
Now, I am not a fan of Lem’s (and no, I don’t think I’d be a fan even if he were translated direct from the Polish—I’m allergic to that variety of heavy-handed, supercilious irony, and I dislike even more his contempt for all other science fiction writers), but this is ridiculous. I could understand, sort of, translating from the French if the original were in, say, Abkhaz, but can it possibly be that hard to find translators from Polish?