I originally thought this would be the last book I reviewed in 2007, but several chapters at the end didn't get finished until today, so it's the first in 2008.
To the best of my knowledge, The Cyberiad is Lem's most famous book. I've read it before - years ago - and remembered almost none of it. Now I know why. It's not a bad book by any means, but it isn't the type that is going to stick with me in any detailed way.
This is a book of fairy tales set in a very, very vaguely science fiction setting. As fairy tales, I guess they are supposed to have morals, but in most cases I don't see them (I admit to being notoriously dense, however) which just makes them oddly written short stories in to me. Add to that some of the dated technology mentioned (the book was originally published in 1967, so vacuum tubes are in while transistors are not, for example), a plethora of made up words, and a wanton disregard for the laws of physics and rational story-telling and you get a recipe for stories that don't remain in my memory for long.
They're fun as you read them, though, and the last couple are better than the rest, as they bring up philosophical issues with some meat to them. All but the last feature one or two "constructors" - Trurl and Klaupacius - who are robots famed for their ability to create machines to solve problems. With only a couple of exceptions, the stories aren't even related, and make no mention of each other, so they mostly stand on their own.
The most interesting thing to me, though, is that the book was originally written in Polish. The translation to English must have been a nightmare, and Michael Kandel - the translator - deserves a lot of credit for making things come out as nicely as they do. There is wordplay and rhythm in these sentences that must have been a challenge to translate, particularly when combined with all the made up words.
If you're interested in some basically silly short stories that claim to be SF but are - in reality - stretching the limits of even fantasy, check it out.