Hallucinations , a new book by Oliver Sacks, MD, hit store shelves (and e-readers) this month, and—like many of his other books—it is sparking conversations not only in the scientific community but also more widely among the reading public. Sacks is a clinical neurologist and professor at New York University School of Medicine. He is best known for his books that examine case studies from his own research and practice, including The Mind’s Eye, Musicophilia , Uncle Tungsten , The Man Who Mistook His Wife for a Hat , and Awakenings (which inspired the 1990 feature film starring Robert De Niro and Robin Williams). In this new book, Sacks asserts that, contrary to popular belief, hallucinations are not the sole purview of the mentally ill. In fact, they are surprisingly common among individuals with sensory deprivation (e.g., blindness) or medical conditions such as migraine, epilepsy, or Parkinson’s. Many healthy people experience hallucinations in the moments before sleep or upon waking, according to Sacks. Strong emotions associated with major life changes can trigger hallucinations, for example, when a bereaved spouse experiences a “visit” from his or her lost loved one. And of course, hallucinations can be a side effect of medication or intoxicants. Hallucinations is a collection of fascinating stories, anecdotes, and case studies. Sacks describes a woman who hears not spoken voices, but music; a man who smells roast beef when he feels a migraine coming on; and a respected botanist who walks into his lab, only to see himself already at work. Drawing on history, art, religion, and popular culture, Sacks seeks to describe and better understand the experience of hallucination. As a clinician and researcher, he also delves into the biology of the brain and the neurological reasons behind many types of hallucinations. With this book, Sacks hopes to ameliorate some of the stigma associated with hallucinations. In a recent interview with Slate magazine, he said, “I think there’s a common view, often shared by doctors, that hallucinations denote madness—especially if there’s any hearing of voices. I hope I can defuse or de-stigmatize this a bit. This can be felt very much by patients. There was a remarkable study of elderly people with impaired vision, and it turned out that many had elaborate hallucinations, but very few acknowledged anything until they found a doctor whom they trusted.” In a 2009 TED Talk entitled “What Hallucination Reveals About Our Minds,” Sacks provides an introduction to his subject, along with some background on the work that led to his recent book. The 20-minute TED Talk is available free online, so take a look—and let us know what you think. PAR wants to hear from you, so leave a comment and join the conversation!