Books of The Times
By JENNIFER SENIOR

It’s been almost 40 years since Jeff Goldblum appeared in “Annie Hall” as an unnamed party guest who couldn’t remember his mantra. Mr. Goldblum has done very well since then; mantras, alas, have had a rougher go of it. But perhaps it’s time to ask: Must the mantra be forever impugned?

This is one of the many questions that the English science writer Jo Marchant tackles in “: A Journey Into the Science of Mind Over Body.” She’s grown weary of the old Cartesian dualism, which seats the mind at one end of the table and the body at the other, like a married couple with nothing to say to each other.

“Stacked up on one side are the proponents of conventional, Western medicine,” she writes in her introduction. “According to their paradigm, the body is like a machine. For the most part, thoughts, beliefs, and emotions don’t feature into treatment for a medical condition.”

And on the other side? “Everyone else,” she bluntly concludes. Among them: Past-life regression therapists, energy healers, homeopathic doctors — all the peddlers of loosey-goosey gooey-hooey who had Woody Allen running for the hills.

Jo Marchant

Ms. Marchant’s aim in “Cure” is to expose the absurdity of this dichotomy. (Though it feels a little artificial as the book goes on: A number of academics who reject it work at Harvard, hardly a scientific backwater.) Ms. Marchant is careful to emphasize that she will not countenance silliness. She has a Ph.D. in genetics and medical microbiology. The scientific method is her friend.

But Ms. Marchant, the author of “Decoding the Heavens” and “The Shadow King,” wants to acknowledge the alternative therapies that have withstood the scrutiny of Western peer . More broadly, she wants to acknowledge the important and influential of the mind in our overall .

What follows her introduction is a 12-chapter tour d’horizon, with the author crisscrossing the globe to make a detailed relief map of the latest mind-body research. Virtual reality therapy in Seattle! Hypnosis in Northern England! Placebo studies in Italy and Germany!

It’s a familiar format, this jet-pack journalism, and much of Ms. Marchant’s material is familiar too, particularly in the second half of the book. (That stuff about the of friendship and social connections? You’ve read it. Those serene Buddhist monks who spent tens of thousands of hours in ? You’ve read about them too.) Anyone who’s ever picked up a book about neuroplasticity or positive psychology is well acquainted with the general contours of this terrain.

Two things separate “Cure” from other books of this type.

First, Ms. Marchant writes well, which is never a guarantee in this genre; you often must make a choice between authors who understand science but can’t write, and authors who can write but don’t understand science.

Second, Ms. Marchant has chosen very moving characters to show us the importance of the research she discusses — we forget that those who turn to alternative medicine are often people in extremis — and she possesses an equal flair for finding inspirational figures. I will always like a book, at least a little, if it mentions a 102-year-old Costa Rican woman who can recite a six-minute Pablo Neruda poem from memory.

My favorite chapters of “Cure” come mostly at the beginning, when Ms. Marchant discusses the placebo effect. It, too, is a topic some readers may consider old hat, but the studies are irresistible, and they come in an almost infinite variety.

Did you know, for instance, that there are placebo trials involving fake surgery? Surgery! (Not with a general anesthetic. But still.) Or that large-pill placebos work better than small ones? (Which is funny if you think about it, considering they are equally inert.) Or that placebos sometimes work even when we know they’re placebos? (There is, correspondingly, a niche market for placebos online.)

And that’s just the kid stuff. There’s also evidence suggesting that placebos affect the immune system, not just the subjective experience of pain.

“It isn’t trickery, wishful thinking or all in the mind,” Ms. Marchant writes, when explaining the biology of the placebo effect. “It is a physical mechanism, as concrete as the effects of any drug.” What we are swallowing with any pill is essentially an idea: That we will feel better. This belief alone is often enough to trigger the release of our natural endorphins, or dopamine, or whatever other chemical our body was expecting to make or consume if we’d taken an actual drug.

After placebos, Ms. Marchant looks at how researchers are trying to harness the powers of the mind to fight chronic fatigue, irritable bowel syndrome and intractable physical pain. The biological origins of each condition may differ. But what most of the treatments she examines have in common, whether they involve hypnosis or cognitive behavioral therapy or virtual reality, is that they divert our attention away from our ailments.

This deceptively simple idea is one of the most powerful in the book: Sometimes the difference between feeling well and feeling awful is simply a matter of where we direct our attention.

As the book progresses, however, Ms. Marchant starts outlining the ways we can rewire our brains and improve our well-being, and in doing so, she serves up the same old chestnuts — lightly roasted and seasoned for our delectation, perhaps, but chestnuts nonetheless. Again with the mindfulness? Still with the biofeedback? Must we read, for the umpteenth time, about the salubrious effects of faith?

I’m also a little tired of reading about the dangers of rinsing our brains in cortisol. Like most anxious New Yorkers, I’d give half my life savings for my amygdala to scale back its hours. But there comes a point when reading so many studies about the toxicity of stress starts to feel punitive, not informative.

By the end of her book, though, Ms. Marchant has won me over again, with a chapter about the pilgrims of Lourdes. She speaks to a woman named Ann, a depressive with a terrible life story. Why does Ann love Lourdes? “Love is oozing out of the walls.”

Ms. Marchant, a scientist to her bones, notices it too. “Random acts of kindness are the norm,” she writes. “In the baths, volunteers tie pilgrims’ shoelaces.”

If there is one lesson to be drawn from “Cure,” it is this: For the ailing, there is no substitute for face time with someone who cares about your fate. Is Western medicine conducive to such radical intimacy? No. Doctors are forever rushed, harried, swamped. But considering that tenderness costs us nothing, it may be the easiest fix we’ve got.