Michael Pollan is at it again: taking drugs and spinning wild, mesmerizing yarns about being human in a plant world. In his new book, “This Is Your Mind on Plants,” he grows opium poppies and mescaline cacti in his garden, heroically (and miserably) tries to avoid caffeine, and, in general, participates with gusto in our species’ age-old labor of helping the cleverest of plants propagate their genes. He weaves together botany, brain sciences, evolutionary biology and political economy into a sort of grand unified theory of drugs. And, of course, he experiments on himself, with intellectually delectable results. While not as revelatory as Pollan’s major works, this is a wonderful and compelling read that will leave you thinking long after you set it down.

The book has three sections — Opium, Caffeine and Mescaline — each of which ties a scientific and historical exploration of a plant-drug to a small but gripping personal drama. In the first, reprinted with added material from an article first published in 1997 in Harper’s Magazine, Pollan plants opium poppies in his garden so he can experiment with opium tea. This radical gardening act led him deep into America’s “war on drugs” and connected him with rogue gardeners willing to expose two of the lies that war relies on: first, that opium poppies cannot be grown in the United States, and second, that extracting opium from poppies is forbiddingly difficult. It turns out, Pollan learns, that poppies are for sale in standard seed catalogues, and opium goo practically harvests itself. So he proudly watches his poppies grow while nervously eyeing a Drug Enforcement Administration crackdown on other would-be poppy rebels. He has doubts; he has nightmares and anxiety attacks; but ultimately he sticks to his guns, tries his poppy tea, and meditates on the absurdity of a plant being illegal and a garden a crime scene.

Unlike the opium poppy, coffee and tea plants do not press Pollan into service as a propagator. They hardly need to; they have already achieved world domination. Indeed, so firm is their grip on humanity that Pollan’s quest in the caffeine chapter is simply to avoid the omnipresent drug. He wants to experience “doing” caffeine with fresh eyes and no built-up tolerance — a challenge when he (like everyone else) is already “on” caffeine all the time. Withdrawing from caffeine, Pollan faces a crisis of confidence: Can he write the chapter? Is it even worth writing? Is anything worth doing at all? He eventually makes it through withdrawal and writes with characteristic beauty about the intense coffee “trip” he takes when he falls off the wagon. Also characteristically, he spies deeper significance in his experience of decaffeinated apathy. Perhaps, he thinks, it supports the theory that Europe’s switch from the sodden magical thinking of alcohol to the bright, eager rationalism of coffee powered the 17th-century revolutions of Enlightenment, imperialism and capitalism (and, of course, led to the coffee plant’s own extraordinary global triumph, driven by the dedicated service of an intelligent and extremely industrious primate).

The third section focuses on mescaline and Pollan’s often-stymied efforts to experiment with it amid a pandemic, wildfires and a “darkening political season.” Hoping that the drug might help him navigate the accumulating traumas of those unhappy days, he has an eye-opening encounter with the far more significant traumas of the Native Americans who have long been mescaline’s main consumers. He learns about the modern peyote religion, born in the 1880s during one of the many nadirs of European Americans’ attempted genocide. Drug use in this context was not an individual act of rebellion but a collective act to reinforce and sustain a direly threatened community. Awareness of the peyote religion poses an ethical dilemma for Pollan: As its practitioners explain, it requires wild cacti — cultivated plants do not have the same spiritual power. Attention from a best-selling journalist like Pollan could galvanize curiosity-seekers and deplete an already limited resource. Pollan is persuaded. Instead of peyote he experiments with a synthesized form of mescaline and with a different variety of cactus, the San Pedro, that he grows in his garden.

Pollan is an astonishingly good writer, at times intimate and vulnerable, at times curious and expository, always compelling and credible. Reading his writing can be kind of like taking a psychedelic — a literary onomatopoeia. When I put the book down I felt temporarily smarter, more capable of deeper perception of myself and the world around me. It’s a wonderful and important gift.

After coming down from my reading high, though, I have a couple of reservations. First, Pollan’s interests are wide-ranging, but he seems most taken with brain sciences and sometimes flirts with a soft form of pharmacological essentialism — that is, a tendency to reduce drugs’ social and political complexities to the interactions between chemicals and brains. Take, for example, his fascination with the theory that Europe’s 17th-century cultural revolutions were sparked by a switch from drunken to caffeinated brains. Yet according to historian David W. Conroy, alcohol-soaked “public houses” (today’s pubs) served just as well as nerve centers in the next century’s American Revolution. Drug effects surely played some role in these developments, but perhaps not in a neuroscientifically specific way, and they almost certainly operated in the shadow of other, less-sexy but more significant social and political factors.

I also have concerns about Pollan’s drug policy critiques. He can be effective here, skewering the absurdities produced by an irrational and arbitrary war against plant drugs; for example, his garden poppies are perfectly legal unless and until he is aware that they contain opium. Yet historians know that American drug laws are anything but irrational, arbitrary or absurd. Quite the opposite. From Prohibition to the drug war, they have been carefully designed to do exactly what they do so well: police poor and racialized communities. They were never intended to cut off presumptively innocent and well-meaning middle-class White people’s access to psychoactive drugs. Indeed, historically, pharmaceutical “white markets” have seen their biggest booms when the drug war has been at its fiercest. When Pollan bridles that drug laws limit his freedom, and when he ridicules the foolishness of lumping him and his cozy garden with fearsome “addicts” and criminals, he unintentionally reinforces this pernicious drug war logic. It isn’t an insignificant problem. As a historian I’ve seen too many campaigns for reform wane after notching minor victories against drug war absurdities, leaving deeper injustices intact.

These political qualms didn’t keep me from enjoying “This Is Your Mind on Plants.” It’s a lovely book by a deep thinker and a masterful storyteller. I can’t help but hope that such a powerful ally will wade as deeply into drug politics as he does drug neuroscience. The struggle for drug policy reform is an important one, and like the substances he writes about, Pollan has the power to change minds.

This Is Your Mind on Plants

By Michael Pollan

Penguin Press. 274 pp. $28