HYPOCHONDRIA, by Will Rees

As a cultural attitude, “ignorance is bliss” has sort of fallen out of favor. Much more de rigueur: “Do the work,” “the only way out is through,” “see something say something.” Never mind that Thomas Gray’s 18th-century adage happens to be true, and, in the case of the inner machinations of our own physical bodies, ethically uncompromising.

We are a society of hypochondriacs, a band of idiots roving through TikTok and Reddit and Apple Watch data and WebMD for the pseudoscientific meanings of our symptoms, the diagnoses of our own mortality. But as any armchair therapist will tell you, the high of control is short-lived. No sooner do we digest another physiological factoid than the hunger comes back tenfold, in the form of even more questions than we had before.

This rabbit hole is explored in stylish detail by the English book editor and academic Will Rees in “Hypochondria,” a compact treatise that spirals through memoir, history and theory in an effort to grab hold of its slippery subject.

Rees doesn’t, of course, but that failure only redirects him. Hypochondria, he writes, “is a diagnosis that puts into question how certain we can ever be about any diagnosis,” itself included. “Call it what you will, it’s the uncertainty that interests me, not the labels with which we try to contain it.”

Rees knows the hypochondriac’s plight firsthand. “One day in 2010,” he writes ominously, “I got a headache.” A normal one; not excruciating — but lingering. After a month, a doctor tells him that Rees, like so many undergraduates, is experiencing tension headaches. Rees refuses painkillers — the idea “struck me as irresponsible, even reckless, like disconnecting a fire alarm because it has interrupted your sleep” — preferring a Kafka-inspired campaign “to understand the headache” instead.

Good luck with that, the reader mutters as our author innocently ambles down the path of hypochondriacal no-return, his newly observed symptoms accumulating like a ball of rubber bands. He forgets words and where he’s seen certain faces before, his eye sometimes twitches and coffee tastes metallic and he notices himself hiccupping one to three times per day. (“Can hiccups be caused by brain cancer? I asked Google. Yes, it answered — if it is advanced.”) Doctors fail to find anything wrong.

Here Rees’s writing is at its most acute: in articulating the myopia that has plagued the human brain since its development — particularly those of people with too much time for idle thinking.

This slim book offers no shortage of drama. In addition to his own trials, Rees refers us to Robert Burton’s 1621 “Anatomy of Melancholy” and its cataloging of hypochondriacs who believed their bodies had transmuted into stoneware or glass, as well as the gory dethroning of Hippocrates’ humoral theory of medicine in the 1540s. In 2013, Rees writes, smack in the middle of his own five-year bout, “hypochondria ceased to exist”; the term had been removed from the D.S.M.-5.

Rees originally set out to write “a serious, scholarly study” of the condition “that would diligently chart its development” from ancient Greece to the present. This book is not that one, but something perhaps more interesting, even useful: one mind’s effort to reconcile its impressions of the world, however distorted, with those of a long lineage of thinkers before him, in the process metastasizing a non-theory of hypochondria into a more universal thesis about the enduring power of human doubt.

Rees points out the double confusion of hypochondria — that the term itself has ever been, medically speaking, “suspended in darkness,” as Freud put it in 1909. For Rees, this also applies to the sufferer. “I can think of no better way to describe the lightless place in which hypochondriacs find themselves, their desire for some definite and illuminating understanding that pushes them to grasp, anxiously, at the very limits of their knowledge.”

Rees starts to feel better and moves on with his life, which mostly involves writing about illness and its absence. But timelines, in this book, overlap atemporally, as they do in our own minds. One chapter, originally published as a magazine essay, recounts two weeks of tests Rees underwent following a fever and a possible lymph node spotted on a chest X-ray. This period of biopsies, waiting rooms and medical reports, he writes, left him with a hospital discharge but no certainty that he was, indeed, healthy.

An unexpected addendum mimics the rug-pulling disorientation of the hypochondriac’s self-doubt. A year after the essay publishes, a stranger approaches Rees at an event. “You need to get another test,” the man says. Upon reading the essay, the stranger says, he had but one thought: “This person has lymphoma.” And with that, the reader feels the lights go out on our own smug illusions of certainty.

We don’t know the results of his ensuing M.R.I. “Now, I prefer not to know,” Rees writes. There is no satisfying resolution, for him or for us. The story of our health does not end decisively — until it does.

HYPOCHONDRIA | By Will Rees | Coach House | 230 pp. | Paperback, $18.95