INTRODUCTION Of all the many things humans rely on plants for--sustenance, beauty, medicine, fragrance, avor, Fiber--surely the most curious is our use of them to change consciousness: to stimulate or calm, to Fiddle with or completely alter, the qualities of our mental experience. Like most people, I use a couple of plants this way on a daily basis. Every morning without fail I begin my day by preparing a hot-water infusion of one of two plants that I depend on (and dependent I am) to clear the mental fog, sharpen my focus, and prepare myself for the day ahead. We don''t usually think of caffeine as a drug, or our daily use of it as an addiction, but that is only because coffee and tea are legal and our dependence on them is socially acceptable. So, then, what exactly is a drug? And why is making tea from the leaves of Camellia sinensis uncontroversial, while doing the same thing with the seed heads of Papaver somniferum is, as I discovered to my peril, a federal crime? All who try to construct a sturdy deFinition of drugs eventually run aground. Is chicken soup a drug? What about sugar? ArtiFicial sweeteners? Chamomile tea? How about a placebo? If we deFine a drug simply as a substance we ingest that changes us in some way, whether in body or in mind (or both), then all those substances surely qualify. But shouldn''t we be able to distinguish foods from drugs? Faced with that very dilemma, the Food and Drug Administration punted, offering a circular deFinition of drugs as "articles other than food" that are recognized in the pharmacopoeia--that is, as drugs by the FDA. Not much help there.

Things become only slightly clearer when the modiFier "illicit" is added: an illicit drug is whatever a government decides it is. It can be no accident that these are almost exclusively the ones with the power to change consciousness. Or, perhaps I should say, with the power to change consciousness in ways that run counter to the smooth operations of society and the interests of the powers that be. As an example, coffee and tea, which have amply demonstrated their value to capitalism in many ways, not least by making us more efficient workers, are in no danger of prohibition, while psychedelics--which are no more toxic than caffeine and considerably less addictive--have been regarded, at least in the West since the mid-1960s, as a threat to social norms and institutions. But even these classiFications are not as Fixed or as sturdy as you may think. At various times both in the Arab world and in Europe, authorities have outlawed coffee, because they regarded the people who gathered to drink it as politically threatening. As I write, psychedelics seem to be undergoing a change of identity. Since researchers have demonstrated that psilocybin can be useful in treating mental health, some psychedelics will probably soon become FDA-approved medicines: that is, recognized as more helpful than threatening to the functioning of society.

This happens to be precisely how Indigenous peoples have always regarded these substances. In many Indigenous communities, the ceremonial use of peyote, a psychedelic, reinforces social norms by bringing people together to help heal the traumas of colonialism and dispossession. The government recognizes the First Amendment right of Native Americans to ingest peyote as part of the free exercise of their religion, but under no circumstances do the rest of us enjoy that right, even if we use peyote in a similar way. So here is a case where it is the identity of the user rather than the drug that changes its legal status. Nothing about drugs is straightforward. But it''s not quite true that our plant taboos are entirely arbitrary. As these examples suggest, societies condone the mind-changing drugs that help uphold society''s rule and ban the ones that are seen to undermine it. That''s why in a society''s choice of psychoactive substances we can read a great deal about both its fears and its desires.

Ever since I took up gardening as a teenager and attempted to grow cannabis, I have been fascinated by our attraction to these powerful plants as well as by the equally powerful taboos and fraught feelings with which we surround them. I''ve come to appreciate that when we take these plants into our bodies and let them change our minds, we are engaging with nature in one of the most profound ways possible. There is scarcely a culture on earth that hasn''t discovered in its environment at least one such plant or fungus, and in most cases a whole suite of them, that alters consciousness in one of a variety of ways. Through what was surely a long and perilous trial and error, humans have identiFied plants that lift the burden of physical pain; render us more alert or capable of uncommon feats; make us more sociable; elicit feelings of awe or ecstasy; nourish our imagination; transcend space and time; occasion dreams and visions and mystical experiences; and bring us into the presence of our ancestors or gods. Evidently, normal everyday consciousness is not enough for us humans; we seek to vary, intensify, and sometimes transcend it, and we have identiFied a whole collection of molecules in nature that allow us to do that. This Is Your Mind on Plants is a personal inquiry into three of those molecules and the remarkable plants that produce them: the morphine in the opium poppy; the caffeine in coffee and tea; and the mescaline produced by the peyote and San Pedro cacti. The second of these molecules is legal everywhere today; the First is illegal in most places (unless it has been reFined by a pharmaceutical company and prescribed by a physician); and the third is illegal in the United States unless you are a member of a Native American tribe. Each represents one of the three broad categories of psychoactive compounds: the downer (opium); the upper (caffeine); and what I think of as the outer (mescaline).

Or, to put it a bit more scientiFically, I proFile here a sedative, a stimulant, and a hallucinogen. Taken together, these three plant drugs cover much of the spectrum of the human experience of psychoactive substances, from the everyday use of caffeine, the most popular psychoactive drug on the planet; to the ceremonial use of mescaline by Indigenous peoples; to the age-old use of opiates to relieve pain. That particular chapter is set during the drug war, at a topsy-turvy moment when the government was paying more attention to a bunch of gardeners growing poppies in order to brew a mild narcotic tea than it was to a pharmaceutical company that was knowingly addicting millions of Americans to its FDA-approved opiate, OxyContin. I was one of those gardeners. I tell each of these stories from multiple perspectives and through a variety of lenses: historical, anthropological, biochemical, botanical, and personal. In each case, I have some skin in the game--or perhaps I should say brain cells, since I don''t know how to write about how it feels, and what it means, to change consciousness without conducting some self-experimentation. Though in the case of caffeine, self-experimentation meant abstaining from it rather than partaking, which proved much harder to do. One of these chapters consists of an essay I wrote twenty-Five years ago, when the drug war was raging, and it bears the scars of that period of fear and paranoia.

But the other stories have been inected by the fading of that war, the end of which now appears in sight. In the 2020 election, Oregonians voted to decriminalize the possession of all drugs and speciFically to legalize therapy using psilocybin. A ballot measure passed in Washington, D.C., calls for the decriminalization* of "entheogenic plants and fungi." ("Entheogen," from the Greek for "manifesting the god [divine] within," is an alternative term for psychedelics, coined in 1979 by a group of religious scholars hoping to remove the counterculture taint from this class of drugs and underscore the spiritual use to which they have been put for thousands of years.) In the same election, New Jersey, along with four traditionally red states--Arizona, Mississippi, Montana, South Dakota--voted to liberalize marijuana laws, bringing the number of states that have legalized some form of marijuana use to thirty-six. My wager in writing This Is Your Mind on Plants is that the decline of the drug war, with its brutally simplistic narratives about "your brain on drugs," has opened a space in which we can tell some other, much more interesting stories about our ancient relationship with the mind-altering plants and fungi with which nature has blessed us.

I use the word "blessed" in full awareness of the human tragedies that can accompany the use of drugs. Much better than we do, the Greeks understood the two-faced nature of drugs, an understanding reected in the ambiguity of their term for them: pharmakon . A pharmakon can be either a medicine or a poison; it all depends--on use, dose, intention, and set and setting.* (The word has a third meaning as well, one often relied on during the drug war: a pharma- kon is also a scapegoat, something for a group to blame its problems on.) Drug abuse is certainly real, but it is less a matter of breaking the law than of falling into an unhealthy relationship with a substance, whether licit or illicit, one in which the ally, or medicine, has become an enemy. The same opiates that killed some Fifty thousand Americans by overdose in 2019 also make surgery endurable and ease the passage out of this life. Surely that qualiFies as a blessing. &n.