Nevertheless, and as one would expect, such investigations plunge them into timeless and primal matters of sex, death and mortal illness. Specifically, the book presents a locked-room mystery of sorts: Can it be possible that a woman said to be dying of cancer, and whose philosopher-cannibal-husband left a record of her ­dismemberment, is still alive? Or was she a consensual accomplice to her own murder? This core plot is elaborated in a highly traditional (and satisfying) way: twin investigations, apparently unrelated, which gradually entwine. Amateur detectives who become complicit — and, of course, involved sexually — with their suspects. As in a majority of his films, Cronenberg’s approach to narrative is sturdy and direct, the opposite of avant-garde. His originality is in what he’s driven to show you, the fierce sculptural intensity of his details and his willingness to linger. The tableaus in “Consumed” attain the same level. Taking just one for-instance, a 3-D printer constructs a model of a penis disastrously warped into the shape of a boomerang by Peyronie’s disease (which exists; as many of Cronenberg’s ailments are real as conjured).

Whether to your taste or not, it really shouldn’t be shocking. In fact, such particulars are most likely routinely matched, or surpassed, in the work of thriller and horror writers in the post-Thomas Harris era, when monsters must trump ­Hannibal Lecter or else go home. What’s vertiginous in Cronenberg’s book is that such matters are presented in the absence of a reliably bourgeois moral framework. Instead, Cronenberg details them with a clinical curiosity. Try this: “When a slim-hipped naked young man entered the frame, Naomi immediately knew it was Hervé, even before he walked around the side of the table to place his hooked penis in ­Célestine’s coolly accommodating mouth. He brought with him something metallic that looked like a ray gun from a 1950s sci-fi movie, pale-blue and silver and trailing a black cable behind it. . . . The naked young woman who entered from frame right, however, she did not immediately recognize, even after the woman had knelt at the head of the table in order to kiss and lick Célestine’s mastectomy scar.” Or this: “Nathan zoomed into the photo in front of them. That was ecstasy on her face as she cut herself, not self-pity, not masochistic pleasure. . . . Nathan was shaping the article as he reacted. He would have liked to record these thoughts, just say them to GarageBand so that he wouldn’t forget them, but he was not yet comfortable enough with Roiphe to collaborate in that intimate way, to leave himself vulnerable to the old man’s sarcasm and irony.”

These passages are typical of the book’s descriptive exactitude and flatness, its use of banal signifiers like “GarageBand,” and the constant germane ­citations of psychoanalytic or philosophical brands. The book seems to desublimate itself for you: No sooner does the reader think, “This is like the case of Louis Althusser’s murder of his wife,” than some character makes the comparison for you. The result is provocatively comic, and surreal in the manner of a Max Ernst collage. As Zadie Smith recently wrote, commenting on J. G. Ballard’s “Crash” (a book adapted by Cronenberg to film, and an unmistakable influence on “Consumed”): “Some of the deadening narrative traits of pornography can be found . . . but surely this ­flatness is deliberate; it is with the banality of our psychopathology that Ballard is concerned.”

Such a tone prevails except when illuminated by the characters’ own reactions, and Nathan and Naomi are haphazard guides in this Bosch landscape. Their attitudes are distracted, craven, naïve and occasionally rapturous. They’re rarely caught judging themselves or anyone else. A flash drive full of crime-scene evidence and a newly acquired venereal disease are equally examined for use-value: Could this new thing win me followers on Twitter? Is there a chance it might turn me on, or make my lover helpfully jealous?

In this, Nathan and Naomi are worldly, media-savvy innocents, and innocents are always waiting to be schooled. In the later chapters, and quite ­unexpectedly, “Consumed” gives way to a monologue ­confession by Aristide Arosteguy, the ­aging philosopher-cannibal-suspect of Naomi’s investigation. His testimony becomes, among other things, a tender paean to romantic love, to its persistence, its adaptability, its necessity in the face of death. Of course, Cronenberg being Cronenberg, this also requires a tender paean to another subject: elder sex (its persistence, its adaptability, etc.), especially elder sex of a nonvanilla sort. This may be, for readers the ages of Naomi and Nathan, a taboo more unsettling than cannibalism. Certainly it goes on in far more of your neighbors’ homes. After all, it isn’t only the young and tech-fetishizing among us who are fated for cyborg interfaces. Ever considered the perverse erotic potential of hearing aids? “Consumed” has.