Hallucinations

By Oliver Sacks

NATIONAL BESTSELLER • The "poet laureate of medicine" (The New York Times) and author of The Man Who Mistook His Wife for a Hat weaves together stories of mind-altering experiences to reveal what they tell us about our brains, our folklore and culture, and why the potential for hallucination exists in us all. 

"Sacks has turned hallucinations from something bizarre and frightening into something that seems part of what it means to be a person. His book, too, is a medical and human triumph.” —The Washington Post

“An absorbing plunge into a mystery of the mind.” —Entertainment Weekly

To many people, hallucinations imply madness, but in fact they are a common part of the human experience. These sensory distortions range from the shimmering zigzags of a visual migraine to powerful visions brought on by fever, injuries, drugs, sensory deprivation, exhaustion, or even grief. Hallucinations doubtless lie behind many mythological traditions, literary inventions, and religious epiphanies.

Drawing on his own experiences, a wealth of clinical cases from among his patients, and famous historical examples ranging from Dostoevsky to Lewis Carroll, the legendary neurologist Oliver Sacks investigates the mystery of these sensory deceptions: what they say about the working of our brains, how they have influenced our folklore and culture, and why the potential for hallucination is present in all humans.

• Language: English
• Publisher: Random House Publishing Group
• Release date: Nov 6, 2012
• ISBN: 9780307957252

Oliver Sacks

Oliver Sacks was born in 1933 in London and was educated at the Queen's College, Oxford. He completed his medical training at San Francisco's Mount Zion Hospital and at UCLA before moving to New York, where he soon encountered the patients whom he would write about in his book Awakenings. Dr Sacks spent almost fifty years working as a neurologist and wrote many books, including The Man Who Mistook His Wife for a Hat, Musicophilia, and Hallucinations, about the strange neurological predicaments and conditions of his patients. The New York Times referred to him as 'the poet laureate of medicine', and over the years he received many awards, including honours from the Guggenheim Foundation, the National Science Foundation, the American Academy of Arts and Letters, and the Royal College of Physicians. In 2008, he was appointed Commander of the British Empire. His memoir, On the Move, was published shortly before his death in August 2015.

Reviews for Hallucinations

[tjwilson_1 · Rating: 4 out of 5 stars]

Fascinating account of the wonders of the brain. Had no idea the brain could offer so much emotional and physical protection to the human body in the form of hallucinations. Also, very intrigued by Oliver Sacks's curiosity and found narratives. First book I've ever read Sacks's, and I will surely read more.

[bness2 · Rating: 5 out of 5 stars]

I pretty routinely love Sacks' books, and this one is no exception. Even though I myself have had no hallucinations, induced or otherwise, I have always been fascinated with the topic. I do have lucid dreams, which are sort of related to hallucinations, but still are dreams, nevertheless. Fascinating book.

[sasham-1 · Rating: 4 out of 5 stars]

Very educational but sometimes the technical / medical terms need to be read more than once. This was the first Oliver Sacks book I have read and I some times got the impression it was a drawing together of his other works all of which are referenced numerous times. Also the number and frequency of medical terms mean that some people may be put off entirely.

[gustavog_90 · Rating: 4 out of 5 stars]

Excellent Oliver Sacks as usual. Fascinating cases, insightful hypotheses.

[eclecticdodo · Rating: 4 out of 5 stars]

Oliver Sacks describes in this book many of the varied physiological causes for hallucinations (as opposed to the psychiatric causes). His style of meandering through a subject with the aid of numerous examples is very readable, and I found it utterly fascinating. I particularly enjoyed the section on migraine and now understand a lot more about my own migraine aura.

[nodosaurus · Rating: 3 out of 5 stars]

In this book, Oliver Sacks talks about many types of hallucinations. We first think of visual or audial hallucinations, but any sense can be suspect. He also covers disease-based, fatigue-based, phantom limbs, narcotics, shell shock/trauma, and others. Much of the book is case studies, he throws in some historical context and a little neurology. In some cases he discusses brain imaging relating to the hallucinations. The book seemed long, the case studies didn't really offer a lot of variety in many cases. Yet at times it became very interesting, but it wasn't sustained. There is a lot of information, but it isn't one of his better books.

[mike_b-645943 · Rating: 4 out of 5 stars]

Better than I expected.

[dmturner · Rating: 4 out of 5 stars]

As usual, Sacks does a stunning job of describing disturbing neurological states in such a way that you realize they are normal. He doesn't exempt himself from his kind, respectful, yet dispassionate examining eye, describing his own experiences of alternate realities. When you finish, you understand that our perceptions of reality are seriously skewed, and that the probing alien of today may just be the night-mare or the succubus of yesteryear.

[librarycin · Rating: 3 out of 5 stars]

3.25 starsOliver Sacks is a neuroscientist, and this book includes essays on the topic of hallucinations. There were chapters on blindness, Parkinsons, epilepsy, drugs, migraines, narcolepsy, and a lot more, as well as a couple of chapters on auditory and smell hallucinations.It was mostly interesting, but some parts did lose my interest. His books are like that for me (well, the few that I’ve read).

[ionas_7 · Rating: 5 out of 5 stars]

This is a comprehensive book. It turns out that hallucinations are not just seen by those suffering from mental illness; there are many different types.There is, for example, Charles Bonnet Syndrome, where blind people, those who have not seen anything for years, suddenly begin to “see things”. This is a reaction of the brain to the loss of eyesight.Complex visions may be seen. Incongruous figures may appear in the room. Most people with CBS will be aware that they are hallucinating while some hallucinations may be thought to be real.Faces, text, numerals, or musical notes may be seen.People subjected to sensory deprivation, e.g. those placed in dark tanks of warm water, may experience visual hallucinations.Hearing voices occurs in every culture and has often been accorded great importance.Voices may occur with anyone in situations of extreme threat or danger. Freud himself heard voices on two such occasions. Suicide attempts may be prevented by hearing a voice.Musical hallucinations are not uncommon.Parkinson’s patients, particularly those with post-encephalitic syndromes, medicated with L-dopa are prone to vivid dreams, nightmares and visual illusions or hallucinations.More than a quarter of the author’s patients with ordinary Parkinson’s disease experienced hallucinations after several years on L-dopa.But there is a more malignant form of Parkinson’s which is accompanied by dementia and visual hallucinations even in the absence of L-dopa. Examination of the brain may show abnormal aggregates of protein (lewy bodies) inside the nerve cells.In a chapter on altered states, the author describes his own experiences when taking drugs, e.g. Artane, a synthetic drug related to belladonna. He took twenty pills of Artane and found himself having a conversation with a couple of friends whom he thought had dropped in to visit him but it turned out this was a product of his imagination.The author experimented with many drugs and, among other things, had experiences of seeing a wonderful indigo colour.After taking large doses of chloral hydrate to get to sleep, then stopping, he began to see “bug-eyed monsters” – he had the DTs, delirium tremens. He had hallucinations for nearly 96 hours.Migraines often induce hallucinations too, often complex ones, and the author has also experienced these.There is a chapter about epilepsy which can give “ecstatic” seizures, and one about “hallucinations in the half-field”, when one loses vision in one eye.The final chapters encompass also “psychical” or “paranormal” experiences. OBEs and also visits by angels.One thing that bothers me about Oliver Sacks’ text is that his scepticism of spiritual matters shines through since he tends to classify spiritual experiences as “hallucinations”. I absolutely disagree that a spiritual experience indicates something wrong with the brain, on the contrary!I found the book fascinating; it introduced me to all sorts of experiences that I knew nothing about. Sacks’ language is not just extremely rich but filled with specialized words that not many will have heard of; neither are these likely to be found in the dictionary.I recommend the book for those interested in the brain and its abnormalities and will be reading further books by this author.

[detailmuse · Rating: 3 out of 5 stars]

From the Introduction:Here, then, is a sampling which I hope will give a sense of the great range, the varieties, of hallucinatory experience, an essential part of the human condition.“A sampling” it is -- essentially an accumulation of patient experiences that showcase the variety of neurological (note: not psychiatric) hallucinations, organized into chapters by sense (sight, sound, smell, etc.) or cause (sensory deprivation, intoxicants, Parkinson’s Disease, epilepsy, migraine, etc). And a “great range” it is -- the variety of experiences and the rates of incidence do suggest a commonality to the human condition. (Still, Sacks several times cautions against casually reporting hallucinations: “the single symptom of ‘hearing voices’ could suffice for an immediate, categorical diagnosis of schizophrenia even in the absence of any other symptoms or abnormalities of behavior.”)The book was interesting to read and somewhat informative (there is almost no exploration of the underlying science). But it’s rarely engaging (the exception being a chapter about Sacks’ personal experiences with transcendent/ intoxicant drugs). I love a narrative, I'll poke around in an encyclopedia, but this felt too much like reading a dictionary.It is interesting that, near the end of the book, I happened to be listening to a Science Friday podcast with neuroscientist David Eagleman, who talked about timing in the brain -- our temporal perception of action first then effect, and the problem of misattributing action/effect:Schizophrenia might fundamentally be a disorder of time perception. {…} You’re always generating an internal voice and listening to it. {…} But imagine you got the timing wrong, so that you think you heard the voice before you generated it. That would be an auditory hallucination. You’d have to interpret that as somebody’s else’s voice. {…} Instead of pumping people full of meds, what if we could just sit them down and have them play video games that recalibrate their timing?I know: Sacks is a practitioner while Eagleman is a researcher. But that’s the kind of scientific/exploratory material I'd expected here.(Review based on an advance reading copy provided by the publisher.)

[les121 · Rating: 4 out of 5 stars]

Hallucinations is not my favorite Oliver Sacks book, but it’s still quite interesting. I had no idea that there were so many different types and causes of hallucinations. Even though some readers may find the theme and a few of the cases repetitive, it’s well worth sticking with it for Sacks’ personal anecdotes. This is the first book of his I’ve read where Sacks reveals more about his own life experiences, and it was the highlight of the book for me. Overall, Hallucinations isn’t quite as outstanding as The Man Who Mistook His Wife for a Hat and An Anthropologist on Mars, but I still quite enjoyed it.

[sheiladeeth_1 · Rating: 4 out of 5 stars]

I’d always imagined hallucinations were dangerous, scary and rare; nothing like those tricks of imagination and under-stimulated hearing on a silent night. A voice says your name when nobody’s there—that’s just a dream isn’t it? Seeing those pulsating puddles of light before a migraine? But Oliver Sacks looks for the common cause, and combines the common experience with the strange, making his book Hallucinations an oddly immediate and compelling read.Have you ever wondered why tired and stressed out pilots might see alien spacecraft, or where the universal monsters of fairytales come from. The mind plays intriguing tricks, it seems. And while this book includes rather more drug-induced visions that I’d expected, it also lumps together the ordinary and mundane with the only slightly odd and the increasingly strange.The book touches on PTSD and its effects on the brain, stress and the illness once termed hysteria, cause, effect, and different types of memory. It’s an absorbing, endlessly fascinating read, and it’s far more immediate and personal than I’d expected. Not my favorite book by Sacks, it’s a thoroughly good read just the same.Disclosure: Bought at an airport bookstore for reading on a plane.

[dbsovereign · Rating: 4 out of 5 stars]

Oliver Sacks helps us see ourselves transformed into magical beings who can recreate the very fabric of our lives. When we see that what we have always done is actually the mind at variance with itself in some aspect, it can become pretty heavy. In a good way. Fun investigation into how many of us can be in thrall to these either pesky [or enthralling] apparitions.

[melydia_1 · Rating: 3 out of 5 stars]

More about hallucinations than you ever wanted to know. It starts out kind of neat, learning about the hallucinations brought on by sensory loss or drug use, but it gets very repetitive.

[kittyjay · Rating: 3 out of 5 stars]

I'll confess that this is the first Oliver Sacks book I have read, although I have seen his work mentioned all over and have always been intrigued. I was not disappointed with Hallucinations, an engaging book that covers hallucinations not caused by psychosis, such as seen in schizophrenia.

The hallucinations Sacks covers are diverse and cover an array of causes: from Charles Bonnet syndrome to sensory deprivation, from sleep paralysis to phantom limb syndrome. Together with a variety of historical sources and patient accounts, he has pulled together a book that covers everything but psychosis. Some hallucinations have roots inside the brain, such as the prelude to an epileptic seizure, while others come from more nebulous sources, like grief or trauma. He even delves into intentional hallucinations, the kind caused by taking psychadelic drugs, which he apparently has ample experience with.

Sacks writes fluidly and has a wry sense of humor that crops up every now and again; though he occasionally delves into decidedly more than "pop" neuropsychology, I never felt bored reading it.

Definitely interesting to those who are curious about the brain and its often strange workings.

[kamgeb · Rating: 4 out of 5 stars]

As always Oliver Sachs writes fascinating books with really interesting neurological stories. This also adds his usage of drugs which I had never heard of before. My only difficulty was that by the end I was getting a bit bored. The hallucinations I found more interesting were in the beginning of the book.

[jimocracy · Rating: 3 out of 5 stars]

The individual cases of various patients provided a robust and varied picture or hallucinations from a neurological perspective. However, the best part of the book was the author's own accounts of psychotropic drub use. Over all, I enjoyed the subject and gained some insight to something I had previously thought of strictly in terms of mental disorders.

[laurieindra · Rating: 3 out of 5 stars]

Not the best Sacks I've ever read, but still interesting. Learned some new things, that's always a plus.

[conniejo_1 · Rating: 4 out of 5 stars]

I've read The Man Who Mistook His Wife for a Hat, and this was along the same lines. Rather than being a series of case studies, this book looks at hallucinations topically. Different chapters cover scent hallucinations, hallucinations that occur during and around sleep, drug-induced hallucinations, phantom limbs, visual hallucinations in patients that have gone blind, have different types of brain injuries, different types and feelings for hallucinations, etc.I loved the way the topics and chapters were organized. Sacks is also great at covering interesting topics and providing just enough of an explanation without getting too technical. And he uses cases to illustrate each topic and chapter, with accounts from different doctors and patients.A very interesting book. I read it over the course of a few months, but it was always easy to pick back up and get into, since the chapters read like their own separate topics. I plan on reading Awakenings next.

[ursula_2 · Rating: 3 out of 5 stars]

Oliver Sacks is a neurologist who's written a number of other books that I haven't read. Through the course of Hallucinations, I was reminded that I hadn't read these other books, since from time to time he would mention a case and then follow up with "which I described in more detail in my book ____." I appreciate that he didn't want to retread ground that was covered elsewhere, but sometimes it felt a little like I was reading a bibliography, or listening to a series of movie trailers. Aside from that, this was an interesting look at a large range of things that can be classified as hallucinations. You know how sometimes when you're laying in bed at night with your eyes closed and you'll start to see patterns? Mine are usually kind of like an optical illusion - they'll be a series of shapes that seem to be moving toward me or away from me. I didn't realize those are hallucinations, but they are. The ones we typically think of are covered, of course, including ones induced by drugs and hallucinations that involve each of our different senses. The occurrence of phantom limbs is talked about, and I thought this was one of the more fascinating sections. The relationship between what the eyes see and the brain knows is complicated, and although the brain has a long memory for things it hasn't seen in a while, it does eventually forget. This seems to be a cause for pain in a phantom limb or for feeling like a body part that has been immobile and invisible to you for a long time no longer belongs to you. It wasn't extremely in depth about any particular type or cause of hallucinations, but instead provides a good overview. I stopped the audio a number of times to look up more information about occurrences he described just because some of them seemed too wild to be true, but of course they were true. What more can you really ask for in a book about hallucinations than to be entertained and left with a little wonder and head-shaking at the odd and amazing things that our brains can do?

[bragan_8 · Rating: 4 out of 5 stars]

Neurologist Oliver Sacks turns his attention to the topic of people who see (or hear, or, occasionally, smell or feel) things that aren't actually there. There's a little bit of overlap here with some of his earlier books, but I'd say there's more than enough that's new to make it worthwhile even if you've read everything else he's written. It's not an exhaustive look at the topic of hallucinations, because he doesn't really get into hallucinations that come with psychosis, such as schizophrenia -- a topic that seems like it could well fill another whole book by itself. He talks about a huge variety of other things that can cause hallucinations, though. Indeed, I had no idea there were so many things that could cause hallucinations! There's blindness (total or partial) or sensory deprivation, which can lead to the brain inventing images to fill the nothingness. There's drugs such as LSD, of course. And a number of diseases, including some I never would have associated with hallucinations. Migraines, which often come with visual auras, but can sometimes get even weirder. Fever delirium. Brain damage. Perfectly ordinary brains getting confused on waking up or falling asleep. And lets not forget phantom limbs...As usual with Sack's books, there are a lot of fascinating descriptions of things his patients and others have experienced, intermixed with some layman's-level explanations about what's going on in the brain when this stuff happens, at least as far as it's actually understood. There are also some relevant accounts of the author's own personal experience; among other things, Sacks took a surprising amount of drugs back in the 60s. In the end, also as usual, I'm left with a bemused appreciation of how incredibly complex our brains are and just how deeply weird things can get when they go a bit wrong. I also keep expecting to start hallucinating myself any moment, but hopefully that will pass.

[y2ash · Rating: 4 out of 5 stars]

I've been intrigued by Oliver Sacks when I first saw his book The Man Who Mistook His Wife for a Hat. I still haven't read it yet but I will. The reason I read Hallucinations was because it was for one of my book clubs. Thank Goodness for that book club.

In Hallucinations, Dr. Sacks explains that hallucinations are not by-products of people inflicted with dementia and psychosis alone. The very sane and the very mentally stable can have them too. There are various ailments and disorders that can cause them such as Charles Bonnet Syndrome (CBS), Parkinson's, Narcolepsy. Also, certain drugs can cause altered states that can lead to hallucinations.

Sacks also went into the different types of hallucinations: visual, auditory, and tactile. Also, afflictions that really wouldn't be consider a hallucination, at least by me, like phantom limbs, migraines and certain sleep disorders. Infused within are brief history lessons about when was the first occurrence of the disorder or syndrome, etc.

Also, Sacks also gives personal insights like when he momentarily became addicted to drugs and had a very bad trip with hallucinations galore. It was funny. I really enjoyed this book and will definitely read more.

[gypsysmom_1 · Rating: 5 out of 5 stars]

Oliver Sacks was a brilliant neuroscientist but an even better writer. I have read at least 6 of his books and enjoyed every one of them. More to the point, I learned something from each one. This book is no exception. Unfortunately Sacks died a few weeks ago and, unless he had something in the works, his autobiography, On the Move, will be his last book. There are some of his older books that I have not read and I will savour them.If I had ever thought about hallucinations I guess I would have thought that they were something people with mental health problems experienced. As Sacks has shown in the book hallucinations can be the result of many diseases or conditions and most of them are due to some change in the brain. Hallucinations can be visual, auditory, tactile or olfactory. They can last for a few seconds or persist for weeks. Many famous people including Sacks himself have experienced hallucinations. Most people are reluctant to tell others that they have experienced hallucinations, fearing that doctors will diagnose them with a mental illness. That is a possible result. In the chapter called “Hearing Things” Sacks relates a 1973 experiment in which 8 people presented themselves at a variety of hospitals across the United States with a complaint of hearing voices. “They told the hospital staff that they could not really make out what the voices said but that they heard the words ‘empty’, ‘hollow’ and ‘thud’. Apart from this fabrication, they behaved normally and recounted their own (normal) past experiences and medical history.” All of these people were admitted to hospital for up to two months and diagnosed with schizophrenia or manic-depressive psychosis. None of the medical staff discovered that these patients were in an experiment. Interestingly, real patients figured it out. One said “You’re not crazy. You’re a journalist or a professor.”I would think that people who have experienced hallucinations and not told anyone would be encouraged by this book. It is obvious that hallucinations are much more common than is believed. Since they can be signs of some abnormality in the brain it would be important to have the issue discussed and examined.

[bobbieharv · Rating: 3 out of 5 stars]

He's lost his touch a bit - this was much drier than his earlier work. Most interesting and juicier chapter was, of course, the one about the effects of the prodigious quantities of drugs he took in his student days! Found myself skimming by the end; it was all quite repetitive.

[muddyboy · Rating: 3 out of 5 stars]

This book is a one beat drummer. When you first read it you think this is fascinating but then by chapter nine or ten if feels like you have read it all before. Dr. Sacks gives hundreds of examples of hallucinations and he divides them up based on their causes like loss of eyesight, sensory deprivation and brain injury for example. His sources include, himself, his patients, people who have written to him and other people experiences that he has read about. But the hallucinations start to sound the same and so after initial excitement my interest tailed off. Perhaps if I or my immediate family suffered from this I would have had a more sustained interest..

[judy_aa · Rating: 4 out of 5 stars]

Hallucinations is a fascinating book but is the first of Sacks' works to, in my humble opinion, overstep scientific bounds. Hallucinations are tricky things and to lay out a history of hallucination by disorder based in large part on completely anecdotal evidence grates my skeptic's soul. At one point he even describes the hallucination of loved ones after death as a normal "neurological response to grief" but then fails to tie this to any empirical data. Or I was hallucinating at that point.

His chapters on hallucination as a consequence of illness, prescription side-effects, sensory deprivation, sleep paralysis and grief are very interesting. Chapters on hallucinations as caused by psychedelic drugs are much less interesting, almost self-serving. Pages and pages of descriptions of trips that all sound like Jefferson Airplane lyrics are for the most part, only of interest to the author.

Still, the book is well worth reading if you have an avid interest in neurosciences (Sacks assumes the reader has a working knowledge of the main parts of the brain and their functions and does not slow down for expositions in this area) and if you are fascinated by the blurry line between reality and dreams and dreams and hallucinations.

[tangotango-1 · Rating: 5 out of 5 stars]

Sacks liest sich leicht und unterhaltend. Seine Bücher sind immer lehrreich; ich habe eine Menge zu Halluzinationen und Illusionen gelernt: Es gibt nicht nur visuelle, sondern auch akustische, olfaktorische und perzeptuelle, die sich auf Gefühlszustände beziehen (nicht nur Déjà vu und Jamais vu, sondern z.B. auch Gefühle von übermäßiger Vertrautheit oder Fremdheit).Und vor allem finden sich so viele Bezugspunkte zum tatsächlichen Leben. Ich selbst habe unter meinen Verwandten Menschen mit einer seltenen Form von Epilepsie und mit einer beginnenden Makula-Degeneration (eine relativ häufige Augenerkrankung). Zu beiden Krankheiten gibt es interessante Fakten.Sacks schreibt aber auch deshalb interessant, weil er sehr viele Beispiele von bekannten Persönlichkeiten bringt und zeigt, was an ihnen pathologisch war. Er versucht, die zunehmende religiöse Verklärung von Dostojewski zu erklären (manche Formen von epileptischen Illusionen stellen eine sehr starke Erfahrung von „Gottesgegenwart“ dar), mutmaßt, ob Johanna von Orleans eine bestimmte Art von Epilepsie hatte, zitiert Nabokovs Erfahrungen mit Illusionen, nennt Schriftsteller, die eine tatsächliche „Stimme“ der Eingebung hörten wie Rilke, Yeats, Homer, erklärt, welche physiologischen Grundlagen von über die Hirnrinde wandernden „Migräne-Gewittern“ sich in weltweit ähnlichen optischen Mustern wiederfinden, ob in der Aborigine-Kunst oder in Zackenband-Mustern von Swasi-Keramik, und welche neurologischen Grundlagen die Arabesken der maurischen Kultur haben.Er beschreibt, welche Arten von bewusstseinsändernden Zuständen verschiedene Rauschmittel (oder deren Entzug) auslösen (er hat selbst in den 1960er Jahren ziemlich intensiv mit Drogen experimentiert) – sehr interessant dazu fand ich die extrem übersteigerte Farbwahrnehmung z.B. im Peyote-Rausch und Sacks erfolglose Suche nach dem wahren Indigo, das er nur einmal im Leben sehen konnte.(Er bringt auch Anekdoten wie die eines Bekannten des Komikers Robin Williams, der sich vorbeugend gegen einen durch Lachen ausgelösten Bewusstseinsausfall immer auf den Boden legt, wenn er ihn trifft).Und Sacks ist so ein richtiger Gelehrter vom alten Schlag, der sich für sehr viele Gebiete interessiert, kunst- und literaturbegeistert ist. Und der sich nicht nur für die medizinische Seite seiner Patienten interessiert, sondern auch einen zutiefst menschlich-warmherzigen Zugang zu ihnen hat.

[gglusman-660560 · Rating: 4 out of 5 stars]

Excellent Oliver Sacks as usual. Fascinating cases, insightful hypotheses.

[lauriebrown54 · Rating: 5 out of 5 stars]

The most people think of hallucinations as things on people suffering from a psychosis have, it looks like the majority of hallucinations aren’t caused by psychosis at all. There are all sorts of hallucinations that arise from all sorts of disorders, including migraine, Parkinson’s, sensory deprivation (including loss of sight for whatever reason), and falling asleep and waking up- this last type can be terrifying. The book starts with one disorder, Charles Bonnet Syndrome, which sometimes occurs in people who have lost their sight. Suddenly, they will begin to see again- except they are the only people who can see the things. Once told that the people (or whatever) are not real and that there is nothing wrong with them, some patients actually find the illusions interesting and amusing and even miss them when the hallucinations abate. Those things we ‘see’ in the dark as we’re falling asleep are hypnagogic hallucinations; they usually have no emotional impact. Hypnopompic hallucinations and sleep paralysis, however, can be terrifying. Occuring as the person wakes, these hallucinations happen with they eyes open and are projected into the external environment and seem real- the monster is in your bedroom. Add sleep paralysis, where the mind is awake but the body hasn’t gotten the message yet, and you can’t fight or escape from the monster, dubbed in the past as the Hag or the Night Mare. Told in Sacks’ usual amusing but informative style, this book is rich in detail but easily understandable by the person with no neurological knowledge. In this book, Sacks tells us something of his own history with hallucinations due to drug use in the 60s. One doesn’t expect this sort of openness in a medical book and I found it amusing as well as instructional; he can look at the drugs from the point of view of both doctor and user, providing an unusual balance. As always with one of Sacks’ books, it’s not to be missed if you have an interest in the brain.