In Pynchon's "Gravity's Rainbow" there was a sequence that noted that the worst fear of a paranoid wasn't that all their fears were true and everyone really was out to get them, but just the opposite: that nothing at all was connected and the universe is just a string of random coincidences that we superimpose a kind of purpose onto to make ourselves feel better.
With that said, let's go watch one of Lem's characters try to solve a mystery! Ha-hah!
I came to Lem mostly through his more SF oriented work (Solaris, Pirx the Pilot, etc) and no matter what the topic there's a certain sensibility that keeps creeping through, a refusal to accept the previously accepted, a probing and questioning tone that stops just short of cynicism and a dark, dry humor that must be a beast for the translators to capture properly. Most everything, no matter how absurd, is played absolutely straight-faced, and you're not sure if you're supposed to laugh or he's just daring you to think that this is funny.
This one is barely SF, although elements keep cropping up here and there. Our main character is a former astronaut that winds up becoming a private detective, if detectives can call themselves that before they solve any cases. A number of middle-aged men have wound up dead, some going completely insane first, all of which seem to follow a certain pattern of visiting hotels and spas before their untimely demises. Is it a serial killer, a mad scientist, a terrorist group testing out a technique before seeking the real targets? Everyone has the dots connected but the picture doesn't make any sense and its up to our hero to recreate the pattern as best he can in the hopes of triggering what killed the other men and with luck not himself in the process. Along the way he converses with various experts who have their own theories, all of which could be true and false simultaneously and very few seem to explain "why?"
This is a talky book, mostly consisting of characters debating their points with each other Asimov-style, with occasional detours into stream of consciousness (the somewhat bravura beginning sequence, where his thoughts skitter along with a ragged intensity, aware of the possible danger if unaware of the source and trying to be on guard by not being on guard) and action (a rather terrifying terrorist attack that may or may not have anything to do with the possible going-ons), which at times can feel like the prose equivalent of a one-room play. It's to Lem's credit that he makes the chatter interesting enough and the central mystery intriguing enough that your attention doesn't flag too much during this version of "CSI: Amateurs", which is fine because it's about the only thing the book really has going for it in terms of heft. If you aren't invested in wanting to find out the ultimate solution to the mystery at hand then you're pretty much here for the travelogue.
Yet he does fill it out in ways that make the book spread out beyond its pages. Our former astronaut is a failed astronaut due to allergies and the slight desperation of that missed opportunity does color the narrative. A brief discussion of astronauts having to deal with the rest of their life failing to live up to the glory of being in space is handled so succinctly and deftly that it conveys the emotion other writers would use to fill up an entire book (and one did, see Dan Simmons' "Phases of Gravity", which is quite good in itself, if the complete opposite of this). The terror attack is truly frightening, both in the seeming randomness of it, and the bloody confusion and chaos that follow, eerily presaging images we see probably too often in our own present day.
But it's still a book that can be read in a scant few hours and lives or dies based on the outcome of its mystery. The explanation here may not satisfy everyone but Lem was never setting out to be the next Agatha Christie, his mysteries come wrapped in theories and ideas, with the conclusion here seeming to be that in a world grown increasingly more complex, we find the patterns that we want to see as a way of convincing ourselves that we have some measure of understanding how this world operates, and its' the thinking that we know what we're seeing that only proves how blinded we've become.