Death by Astonishment: Confronting the Mystery of the World's Strangest Drug

by Andrew R. Gallimore, Graham Hancock (contributor)

For fans of the compelling critical and investigative style of best-selling authors Graham Hancock and Brian Muraresku, the first detailed account of the history and science of the world’s strangest and most mysterious drug - DMT.

DMT is the world’s strangest and most mysterious drug, inducing one of the most remarkable and yet least understood of all states of consciousness. This common plant molecule has, from ancient times to the modern day, been used as a tool to gain access to a bizarre alien reality of inordinate complexity and unimaginable strangeness, populated by a panoply of highly advanced, intelligent, and communicative beings entirely not of this world.

In a story that begins in the Amazonian rainforests and ends somewhere beyond the stars, Andrew Gallimore presents the first detailed account of the discovery of DMT and science’s continuing struggle to explain how such a simple and common plant molecule can have such astonishing effects on the human mind. The history of the drug involves many fascinating characters from the scientific and literary worlds ― including legendary ethnobotanist Dr. Richard Schultes; renegade beat writer and drug aficionado William S. Burroughs; philosopher and raconteur Terence McKenna; and the high priest of the 1960s psychedelic revolution, Dr. Timothy Leary. In the end, the story of DMT forces us to reconsider our most basic assumptions about the nature of reality and our place within it.

Genres: Nonfiction, Science, History, Audiobook, Psychology

320 pages, Hardcover

First published July 1, 2025

Reviews

[Nursebookie · Rating 5 out of 5]

Thank you @stmartinspress for the gifted copy

TITLE: Death by Astonishment: Confronting the Mystery of the World's Strangest Drug
AUTHOR: Andrew Gallimore
PUB DATE: 07.01.2025

If you're looking for a book that challenges everything you think you know about consciousness, perception, and reality, Death by Astonishment: Confronting the Mystery of the World's Strangest Drug by Andrew Gallimore is a must-read. 🧠💫

In this fascinating exploration of DMT (Dimethyltryptamine), Gallimore takes us on a deep dive into the science, history, and cultural significance of this mind-bending molecule. 🌌

From ancient rituals to cutting-edge neuroscience, the book effortlessly blends the spiritual and the scientific, offering a comprehensive look at how DMT has shaped humanity's quest to understand the mind, consciousness, and even the universe itself.
What really stands out is Gallimore’s ability to make complex scientific concepts accessible while maintaining the awe and wonder that comes with exploring the unknown. 🧬✨

He doesn’t just present DMT as a chemical, but as a doorway—a pathway to understanding dimensions, consciousness, and the nature of reality. His exploration of the psychedelic experience will make you rethink what it means to be aware of the world around you.
Whether you’re a seasoned psychonaut or someone curious about the deeper layers of consciousness, Death by Astonishment offers both intellectual depth and a sense of wonder that’s hard to put down. 🌿

It’s a thought-provoking and eye-opening journey that asks: What if the mysteries of the universe are not only out there but also within us?

Highly recommend this one to anyone ready to expand their mind and challenge their perception of reality! 🔮

[Jonathan Lu · Rating 4 out of 5]

Very well researched book whose thesis sounds insane, but cannot be disproved (yet), and is presented almost as whimsically as the DMT-induced experience is itself. You cannot say that this is an uneducated theory, as the richness of this book comes from the in-depth ethnobotanical history of DMT and its discovery, its early experimentation in ethically questionable means by psychologists (mostly among prison populations), and more recent discoveries thanks to the work of Rick Strassman; Gallimore merges this interdisciplinary story well with biochemistry, translational neuroscience to the function of the brain, and Jungian-inspired psychological model of behavior. I was reminded of Rupert Sheldrake, another stellar research scientist, who in the absence of a compelling scientific root turned to spirituality as the drive for his theory… though in Gallimore's case the theory is less spiritual and more alien or at least with intelligent intention. I first came across Andew Gallimore when reading his 2015 paper about integrated information theory published in Frontiers in Human Neuroscience that was one of the most outstanding papers I've ever read about translational neuroscience. That's when I started to learn more about him and his theory first presented in "Alien Information Theory". While pointing out the merits and demerits of his theory, he does not come across so strongly as "this must be the only logical answer" but does present a compelling story that works. It's much less fulfilling to just say that the common trope experienced by about 50% of DMT users is an unexplained human reaction, much how we all have the same genetics and evolutionary anthropology that characterize the similar way that we emote to bipedal organisms - there is no such "why" in observation. It is more provocative to think that the "why" does not belong to us but rather another intelligent species. Makes me wonder if Carl Sagan's portrayal of alien communication being customized through our own brains was inspired by psychedelia, or perhaps our conclusion of information communicated during psychedelic experiences has been inspired by his masterful story. Also makes me wonder more about the mysterious content of jianshoujing mushrooms, as so many of the same adjectives "whimsical, lilliputian, comical, little people, alien" also apply though rarely in China are experiences of abduction, being split apart, tested on scientifically, or what should be terrifying scenarios.

History of plant medicinal chemistry and isolation - Serturner's isolation of morphine from poppy - called alkaloids because of slightly alkaline properties in solution: insoluble in alkaline solution and water, but soluble in acids. Tested on a group of teenagers he found on the streets.

Zerda-Bayon in 1905 seeking human volunteers to test isolated "telepathine" on, the chief commander of Caicedo Military station in Colombia who was interested in experiencing ayahuasca. Tested on himself as well and did not have visions - beginning to understand that it's more than 1 plant. [p29]

William S. Burroughs exploring in search of ayahuasca and coming upon Richard Schultes and Mark Plotkin in sampling B. caapi in the jungles of Colombia, before banisterine / telepathine / yageine were discovered to be the same as harmaline. In depth history of the early ethnobotanical research to discover the sources in South America, and eventually recognizing the same constituents as P. harmala.

History of DMT research, first synthesized by Richard Manske before discovery in nature. Stephen Szara was the first in Hungary to test in patients. Regular self-testing by Timothy Leary who met Nicholas Sand, a clandestine chemist who became the "Acid King" producing 5 million doses of LSD between 1965-1967; and Rick Strassman who received permission to do the study among patients in New Mexico. [p82] Szara later stepped up to have his own brain measured under DMT. This was during a time where Sem-Jacobsen took epileptic or psychotic patients and gave mescaline or LSD, that produced spikes of light information in the temporal lobes. [p173]

Harris Isbell and his experiments on "volunteers" who were prison inmates in Lexington, KY. Ran experiments feeding doses of LSD for up to 85 days in a row, and naturally they developed a tolerance. Also discovered cross tolerance in that they would have a reduced response to psilocybin or mescaline. Found that there was no cross tolerance effect with DMT or tolerance at all - confirmed by Rick Strassman's studies in that intensity of DMT never diminished - until its effect one day just stops, known as "the lockout" [p208]. Reported by users that would do DMT daily for hundreds of days, to suddenly find no more visions - believed that it's an intelligence of DMT to stop the user from experiencing after a certain point.

Karl Beringer in the 1920's first demonstrated improvement in motor control when Parkinson's patients were given harmine and harmaline - due to MAOi activity preventing the breakdown of dopamine. Jeremy Bigwood had the first hypothesis to combine 100mg DMT freebase with harmaline in 1978 [p96].

Jonathan Ott continued trials with Peganum harmala and Desmanthus illinoensis, demonstrating that traditional setting was not necessary for the effectiveness of DMT [p116]

Canadian physician David Lawrence at U of Toronto conducted a quantitative analysis of all Reddit trip reports from 2009-2018 (3778 reports) and found that half mentioned some flavor of an entity encounter. 2020 study at Johns Hopkins polling DMT users anonymously found that 43% responded that they had encountered a being that guided them, 39% called it alien, and 14% called them elves. [p126] In 1909, Raoul Leory a French psychiatrist named the visions Lilliputian - Terence McKenna called "machine elves" [p161]

Experiments of John Lilly who started taking LSD in a flotation tank in 1964 absent of sensory stimulation. Found ketamine to be the most effective due to dissociative effect. While lying in the tank, he saw highly colored 3 dimensional scenes with strange and unusual creatures. "Lilly's brain was constructing a model of the beings with whom he was interacting, in much the same way that the brain constructs - or is induced to construct - a model of the intelligences encountered in the DMT state." [p237]

Is DMT mimicking a dream? No - totally foreign and new imagery vs. dreams that are extrapolations from past experience. "Dreams are not random visions but selective simulations of the waking world." [p150] In fact the experiences of frightening but whimsical creatures doing experiments on you, even killing you, and transporting you up a moving tunnel are consistent with reports of alien abductees.


Julius Axelrod discovered that DMT came from tryptophan. Converted to DMT by indolethylamine-N-methyltransferase (INMT) which is ubiquitous across the animal kingdom [p158]. Studies in rabbits found a molecule in the brain of rabbits that suppresses INMT activity. This peptide is not well studied, but keeps less than 1% of tryptamine in blood samples from converting to DMT but has not been well characterized. DMT is neuro-protective and believed then to be regulated such that it's released in the absence of oxygen, i.e. when dying [p251]

Brain activity under DMT with yes closed was almost identical to normal visual stimulation - "engages the visual apparatus in a fashion that is consistent with actual exogenously driven visual perception." [p218]

Analyzing data from Rick Strassman's study, Gallimore found that DMT "breakthrough" occurs when brain concentration reaches 60ng/ml and peaks at 100 ng/ml. Below 60ng/ml is the threshold where not experienced. Ran a study funded by Anton Bilton who tested hiself with an IV drip to keep a steady level in the breakthrough zone and experience for more than just 15min [p237]

Difference between dreams and waking is the absence of sensory information - good model here about the impact between order and disorder, the fine line that psychedelics gives you the ability to straddle [p180]


Common archetype found in DMT experience: Collective unconscious is a set of innate neural programs (archetypes) shared by all humans (collective), mainly operating outside of conscious awareness (unconscious) that evolved to respond in fast, reliable, and stereotyped ways to all types of humans and other creatures that we might encounter [p183]
Jungian model of the psyche mapped to known functions of the brain [p189]

[Miggins (Hobbit Hole Books) · Rating 5 out of 5]

Deeply fascinating exploration into the strange and wonderful realms of DMT. From the forests of the Amazon, to clinical trials taking place in the western world, Andrew Gallimore covers it all. Whilst I remain skeptical of some of his more speculative claims, I cant help but listen in awe and fascination and a little bit of horror at the worlds that may exist beyond our own

[Jeffrey Powanda · Rating 4 out of 5]

A fascinating book on the history of dimethyltryptamine, a.k.a. DMT, a mysterious serotonergic hallucinogen of the tryptamine family that occurs naturally in many plants and animals, including humans.

Gallimore's book is broader and offers more history than Rick Strassman's groundbreaking book DMT: The Spirit Molecule, but I found that both books complement one another nicely. Strassman's book is good for its rigorous scientific approach and its trip reports. Gallimore's approach is less scientific, more journalistic. It also relies on neuroscience, explaining how your brain uses sensory data to model your world, and that model informs your dreams. But that’s not what’s happening under DMT, which swaps in another world, one radically different from the model your brain has constructed. Other psychedelics stimulate the brain, making the world seem fluid and dynamic, but still based on experiences from the waking world. The DMT world is entirely new and looks nothing like the waking world. Where is the strange, complex, and highly technological information for that new world's model coming from? The DMT experience can't be dismissed as a hallucination. It's something else entirely.

Gallimore stresses the importance of further DMT research; naturally he wants to study and understand the intelligent discarnate alien beings that visit nearly every DMT trip. What is their objective? Speculation about that cosmic mystery makes Gallimore’s book more like an H.P. Lovecraft novel or Budd Hopkins' Intruders, which is about alien abduction.

Of course, the most fascinating thing about DMT is that Western science is only recently catching up with the fact that Indigenous peoples of South America have been using DMT—through yopo or similar snuffs and by shaman-made brews such as ayahuasca—to communicate with
discarnate intelligent nonhuman beings for tens of thousands of years.

The book documents the experiences of many notable DMT researchers, including:
- English botanist Richard Spruce, who discovered the vine used in ayahuasca by indigenous cultures on an Amazonian expedition in 1852
- Beat writer, psychedelic enthusiast, and junky William S. Burroughs
- Dr. Richard Schultes, the father of ethnobotany, who failed to recognize the significance of Burroughs' discovery in 1942
- Dr. Stephen Szára, who conducted the first study of DMT in 1956 and discovered its uniquely visionary properties
- Dr. Rick Strassman, who conducted a landmark scientific study of the effects of DMT on nearly 60 volunteer subjects at University of New Mexico between 1990 and 1995
- Philosopher Terence McKenna, who warned of "death by astonishment" as the possible risk of trying DMT, thus inspiring the book’s title, popularized DMT within the drug counterculture in the 1990s, and gave Dr. Strassman his first hit of DMT
- Psychedelic researcher Dr. Timothy Leary
- Pharmacologist Harris Isbell, who conducted unethical drug tests on prison inmates in Lexington, Kentucky
- Dr. John E. Mack, who investigated the UFO abduction phenomenon, which is eerily similar to the experiences described in many DMT trips

Gallimore, a chemical pharmacologist, neurobiologist, and writer, as well as a pioneer in DMT research, is an eloquent and informative tour guide to the strange world of DMT. Since the 1960s, the secret of DMT, at least in the West, is out, and thousands of people have tried it. Unlike other psychedelics, it doesn't cause you to feel stoned or intoxicated. Instead, it replaces your world completely, catapulting you into a multidimensional realm populated by intelligent discarnate alien beings—including machine elves, insectoid creatures, clowns, lizards, and aliens (a.k.a., the Grays). As Gallimard describes it,

It was now abundantly clear that there was something very special—something seemingly miraculous—about this simplest of alkaloids scattered throughout the plant kingdom with unrivaled ability to rapidly and efficiently dismantle the world and replace it with one that transcended the imagination and the apparent limits of conceivable reality—to switch the brain's reality channel to a bizarre hypertechnological domain filled with advanced and thoroughly alien intelligent beings....DMT was beginning to look less like a drug and more and more like some kind of neuro-molecular technology. But a technology designed by whom and to what end?

It's that last question that leads Gallimore into some wildly speculative areas. It's quite possible that science may never be able to answer that question conclusively. But it's a stimulating journey just the same.

The book offers many photos, including of shamans preparing ayahuasca and artist renderings that attempt to capture the complexity, comedy, and strangeness of the DMT experience.

Gallimore has done many interviews on YouTube to promote his ideas, all based on the latest developments in neuroscience. In a recent interview, Gallimore discusses whether the things that people experience while on DMT trips are internal (i.e., hallucinations) or external (i.e., downloaded from another realm outside the brain): Are DMT experiences spiritual journeys or mind hallucinations? Fascinating yet enigmatic stuff.

[Dan · Rating 4 out of 5]

My thanks to NetGalley and St. Martin's Press for an advance copy of this book that is book a biography of a very powerful way to open the mind, and a possible guide to a new future, one that involves investigations of both inner and outer space.

I have never been much for pharmaceuticals of really any kind. I don't even like aspirin. Growing up in a family of Bronx Irish Catholics I know I have addiction written on my DNA, so I find it is best to just say no to many things. I also have dealt with crippling depression for most of my life, and have been fascinated by the books that have covered psychedelics and other natural ways of finding out what is going on in the brain. As most therapies and even the few times I have taken antidepressants have failed, leaving me feeling much worse than before, I wonder about this drugs, drugs that have been used in rituals since the earliest days of man. So while i might abstain I have done a lot of reading, which I know doesn't equal experience. Few books though have left me so interested, and so confused about what to think as this one. Though I do think I am a better person after reading it. Death by Astonishment: Confronting the Mystery of the World's Strangest Drug by Andrew R. Gallimore is a book I am sure will divide many people, giving both a history of DMT, and what people might be opening, not just the doors of perception, but the doors to encounters with things that might defy our understanding.

The book is both a biography about the substance Dimethyltryptamine, better known as DMT, and its discovery by Western culture, and the strange visions that seem to be shared by many who try the drug. The book begins with different passages about indigenous tribes and their ceremonies, ceremonies that were kept from outsiders for quite a while. There are mentions of William Burroughs and his quest for the yage as he knew it. Descriptions of the diffferent ways the drug is used, processed and ingested. What comes clear is that many people who try DMT, both in the wild and in controlled settings seem to have visions of the same thing. Spiders which would be common as spiders make people uncomfortable, but places that seem similar. Conversations that seem the opposite of good things, and seem to portend of bad things coming. The book travels from the past to the present day, looking at how the study of DMT has changed, but how these visions might be of something that no one has really thought of. Creatures from a higher dimension, or one that we can't see, unless one is under the influence of DMT.

The book is a mix of From Beyond from H.P. Lovecraft and the movie by the same name, mixed with Altered States. What makes much of this information so interesting it the research that Gallimore has conducted. When I first read the foreward by Graham Hancock my neighbors probably felt my eyes roll in my head. Upon reading I found much of this very interesting, with lots of information that was new to me, and even as its oddest, I found myself able to suspend my disbelief. This book I am sure will fall into two camps, possibly even three I will happily put myself in the hmm I kind of want to know more.

Readers of Rick Strassman and Terence McKenna will get a lot out of this. I am sure there will be a lot of college bound kids who will get excited also. Veteran psychonauts will get quite a lot from this, and maybe add to their knowledge in different ways. Not a book for everyone, but one that will fascinate those that know, and even those new to knowing.

[Michiel · Rating 5 out of 5]

Ever since I followed his course on psychedelic neuroscience, I have been a great fan of Gallimore's ideas. Having read Alien Information Theory and Reality Switch Technologies, which were closer to strange textbooks from the future, this book is a more classical popular science. The first dozen or so chapters gave a fascinating overview of the anthropologists who tried to uncover the secrets of ayahuasca, the brew that allows communication with the gods. Gallimore is fond of referring to this as a technology (it requires both DMT as an active compound and an enzyme inhibitor to make it orally active). From this research, they discovered that smoking DMT would lead to a short, very intensive trip ("the businessman trip") that propels the user to a vivid, strange alternative reality filled with creatures that are called machine elves.

Now, it is clear the DMT is something of an enigma, even compared to the wonderous 'conventional' psychedelics:
- Normal doses create extremely potent, short trips for which there does not seem to be any tolerance effects;
- The hallucinations do not seem to be distorted versions of the reality we usually perceive, as is the case with LSD or magic mushrooms; it looks like one enters an entirely new universe.
- Despite this, the molecule is extremely simple (tryptophan with a little tweak), numerous plants contain it in large quantities, and even our bodies are biochemically equipped to produce it.

The intriguing thesis of this work is that the information generated during a DMT trip is not generated within, but rather allows for communicating with an external intelligence. This is without a doubt a provocative statement, which can be placed at the same level as the simulation hypothesis (interesting to think about when in a hot tub). It suits Gallimore that he does his homework and presents a well-reasoned argument. The most exciting part might be the very concrete experiments he proposes to allow psychonauts to be in a prolonged DMT state to explore the hyperspace.

The most interesting aspect of DMT is its wide variability and unique pharmacokinetic properties. It doesn't give access to new worlds, but it does provide access to new world models.

[Christie Murray · Rating 5 out of 5]

WOW! First of all, my thanks to NetGalley and the publisher for allowing me a copy of the ARC audiobook in exchange for my honest review. I received this audiobook and didn’t really know what to expect going in. Typically, I like to read books about psychology and neuroscience, but knew nothing about DMT. This book had me fascinated and hooked by the end of the first chapter. Each chapter was just as awe inspiring, and by the end of each chapter I had more questions I wanted answered and then in the next chapter he would go into answering those questions which would lead to more questions….. The scientific data is crazy but the experiences of the users is unlike anything I have ever heard of. I am now going to go further down this rabbit hole looking into documentaries and other books but really this book is the most is so comprehensive and most up to date. Also, the authors voice is beautiful. I think if I had tried to read this in book form, it may have felt a little heavy, but because of the way it was read by the author, I felt that I was able to easily comprehend everything. HIGHLY RECOMMENDED #netgalley #deathbyastonishment

[Gary Hibbard · Rating 5 out of 5]

Death by Astonishment by Andrew Gallimore is part history lesson, part science briefing, and part mind-bending speculation on the role of psychedelics in human culture. Gallimore does a stellar job tracing humanity’s long relationship with plant-derived DMT, delivering rich historical details without falling into the trap of romanticized storytelling. I especially appreciated how he kept a clear line between fact and personal interpretation—he doesn’t just tell you when he’s speculating, he waves a flag and points at it.

The book also casts a wider net than just DMT, weaving in LSD and psilocybin to show the broader psychedelic tapestry. It’s refreshing to see an author so openly leaning into the future of research, especially in a field where curiosity often outruns funding.

If I had one wish, it would be for a deeper dive into the variations of the DMT molecule—particularly 5-MeO-DMT, which gets little more than a passing glance. That omission feels like leaving a fascinating chapter unopened. Still, for anyone curious about the past, present, and possible future of psychedelic science, this is an engaging and even-handed read.

[Eric T. Voigt · Rating 5 out of 5]

Full of trip reports, which you KNOW I love. Only one chapter got a little crazy, where he floated the theory that when someone enters the DMT state they're actively accessing another dimension of reality, as opposed to it just being stuff made up in their own mind. Though... how DO people come up with all that shit? I mean, people are constantly coming up with new things, right? Why shouldn't the imagination be expected to render ridiculously complex scenes under the influence of highly potent drugs? At least that's where I'm standing on it.

[Bradley Knight · Rating 5 out of 5]

Death by Astonishment is a captivating dive into the enigma of DMT, and I’m giving it a well-deserved 5 stars. As someone intrigued by DMT after hearing about it on podcasts, I was drawn to this book because of Gallimore’s academic credibility, which lends a unique legitimacy to his exploration of this mind-bending substance. His ability to combine rigorous science with profound philosophical questions makes this a must-read for anyone curious about consciousness, psychedelics, or the nature of reality.
Gallimore’s main focus is to unravel the mystery of DMT, tracing its history from its use in tribal rituals to its modern fascination among psychonauts. He delves into the provocative question of whether the vivid DMT realm—populated by entities and alternate realities—is a genuine dimension we tap into or merely a hallucination. What’s striking is his discussion of the consistent experiences reported across users, which challenges the dismissal of DMT visions as mere brain tricks. I found his theory that DMT might grant access to a real, alternate realm particularly compelling, as it resonated deeply with my own experiences.

His discussion of alternate realities felt like a validation of the profound sense of “otherness” I’ve experienced, making the book not just informative but personally transformative.
What sets this audiobook apart is Gallimore’s engaging narration. His passion shines through as he reads, making complex scientific and philosophical ideas accessible and gripping. Every section, from the historical context to the speculative theories, held my attention equally—I couldn’t pick a favorite. His clear, well-structured explanations ensured nothing felt confusing or out of place, which is a testament to his skill as both a scientist and a communicator.
This book earns its 5 stars for its seamless blend of science, history, and bold inquiry, coupled with its ability to resonate with my own DMT journeys. It’s a rare work that appeals to psychonauts, scientists, spiritual seekers, and anyone intrigued by aliens or psychedelics. However, its far-out concepts might be a stretch for those not ready to question reality itself. Reading Death by Astonishment has deepened my conviction that there’s an intelligence within the DMT realm and sparked a desire to explore further. Gallimore has not only illuminated the strangest drug but also challenged me to rethink the boundaries of consciousness. Highly recommended for the open-minded!

[Red Goddess Reads · Rating 5 out of 5]

ALL THE STARS! Be sure to listen to this one on audiobook! Not only is the author‘s voice, simply dreamy, but I feel like I just took a college course more interesting more fascinating than anything I ever took in my school days. There is not a single moment I was bored or lost only endlessly fascinated!