This year I read two Stanislaw Lem novels I’d never read before. The Invincible didn’t impress me, but The Investigation is one of his better books.

The Investigation is Lem’s take on the British mystery. As you might expect the subject isn’t the usual mundane murder: Lieutenant Gregory of Scotland Yard is assigned to look into reports of dead bodies found moved with no one around to move them. It seems corpses are getting up and walking.

Generally[1] I think Lem is at his best in his satirical books, like The Cyberiad, The Star Diaries, and A Perfect Vacuum. The Investigation isn’t one of those, but it’s not dry and numbingly earnest like The Invincible. Lem’s prose is good here, with sharp and memorable descriptions, as when Gregory looks at his fellow train passengers and sees “a sea of accidental faces.”

The Investigation is set in detective-novel England as seen from Poland. In the first few pages we hear of places like Engender, Planting, and Spittoon, and minor characters with names like Thicker and Samuel Filthey. Lem drops these into an entirely straight-faced conversation about animate corpses. It reads like a CSI briefing done in Monty Python voices. Lem surrounds straight man Gregory with interestingly grotesque characters.[2] The best is the birdlike, irascible statistician Sciss, who is incensed by the suspicion that someone might be making fun of mathematics.

Where The Investigation shines is in its surrealism. Lem writes like a dream here, literally: when he drops in a dream sequence it’s not a typical allegorical novel dream, it actually has the disjointed, illogical feel of a real nightmare. Yet it’s still one of those dream sequences you don’t initially realize is a dream, which says a lot about the novel’s tone. Gregory is, after all, investigating walking corpses. Meetings with his superior often take place at night, or in darkened rooms, as if Scotland Yard has instituted mood lighting policies. The case culminates with the nightmarish image of a body moving like a wind-up toy, and I can’t imagine a horror movie pulling off a creepier image than the one The Investigation evoked in my imagination.

The more impossible the case seems the more Gregory moves out of the ordinary world, and the more alienated he becomes. His life outside Scotland Yard is a series of small awkward failures to connect to other people, from the bartender whose simple questions about dinner he’s too abstracted to understand to a humiliatingly unsuccessful attempt to give a few coins to a beggar. Gregory is ultimately so confused that he walks down a tunnel, finds another person blocking his way, and only belatedly realizes he’s walked into a mirror.

Like the astronauts in The Invincible, Gregory is dealing with an apparently intelligent phenomenon that may have no intelligence behind it at all. Sciss’s best explanation for the animate corpses is essentially that some random physical phenomena happened to come together in just the right way to make the dead walk. For Gregory this calls to mind a metaphor of the universe as a bowl of soup in which bits randomly clump together to form something whole. Improbable, but as Lem wrote in another novel, mathematically improbable events sometimes happen anyway. Lem was seemingly fascinated by randomness and probability, returning to the theme over and over. (One of the fake book reviews in A Perfect Vacuum covers a book arguing that if the laws of probability are true then the universe itself, being so improbable, cannot possibly exist.) Lem’s characters seek order in statistical chaos. Many of his novels hinge on distinguishing between meaningful, intelligent phenomena and pareidolia: the misapplied pattern-seeking that, for instance, lets us see faces in clouds. His aliens are really alien. Is Solaris bringing visitors’ memories to life for a reason, or is it an autonomic response, like white blood cells reacting to a virus? Is it possible, without anthropomorphizing, for humans to understand what’s happening on Eden? Most of Lem’s stories and themes come back to the limits of human ability to comprehend an infinite, incomprehensible universe.[3] (In this Lem has a weird thematic parallel to H. P. Lovecraft, although happily Lem’s preoccupation with incomprehensibility is based in a sense of wonder, not xenophobia.) The Investigation takes these themes out of their science fictional context and applies them to the detective novel.

How readers interpret the genre of The Investigation will affect how they interpret Sciss’s theory. Gregory can’t decide what genre he’s in. Sometimes he’s seduced by Sciss’s ideas—if the human mind can’t understand everything, he reasons at one point, maybe it’s irrelevant whether an explanation seems to make sense. Sometimes he’s not buying it: the outbreak of walking dead must have some human intelligence behind it, and he increasingly suspects Sciss himself. But because the name on the cover is Stanislaw Lem and not Agatha Christie, the reader knows the impossible may be happening.

And that’s what Gregory ultimately confirms. But his superintendant has a more mundane theory—a truck-driving prankster—that almost fits. And it’s a tidy theory, since the suspect has since died and wouldn’t be inconvenienced by the accusation. In the end it’s not clear what Scotland Yard’s going to go with. Is a tidy but probably wrong explanation better, or an unsatisfactory mystery? Lem, as you might expect from somebody who lived in Communist Poland, suggests the authorities would rather be satisfied than right. The real horror isn’t the walking dead—it’s the thought that the universe might be too big, random, and weird for human beings to get their heads around.