Have you ever seen something that wasn’t really there? Sensed someone following you and turned around to find nothing?

Hallucinations don’t belong wholly to the insane. More commonly, they are linked to sensory deprivation, intoxication, illness or injury. Hallucinations can be brought on by a simple fever or even the act of waking or falling asleep, when people have visions ranging from blobs of color to beautifully detailed faces or terrifying ogres. Those who are bereaved may receive comforting “visits” from the departed. In some conditions, hallucinations can lead to religious epiphanies or even the feeling of leaving one’s own body.

In Hallucinations, the bestselling book now out in paperback, Dr. Sacks weaves together stories of his patients and of his own mind-altering experiences to illuminate what hallucinations tell us about the organization and structure of our brains, how they have influenced every culture’s folklore and art, and why the potential for hallucination is present in us all. Book signing to follow.