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 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 religions epiphanies.

Originally published by Knopf in 2012.

Silent multitudes : Charles Bonnet syndrome -- The prisoner's cinema : sensory deprivation -- A few nanograms of wine : hallucinatory smells -- Hearing things -- The illusions of Parkinsonism -- Altered states -- Patterns : visual migraines -- The "sacres" disease -- Bisected : hallucinations in the half-field -- Delirious -- On the threshold of sleep -- Narcolepsy and night hags -- The haunted mind -- Doppelgängers : hallucinating oneself -- Phantoms, shadows, and sensory ghosts.