Hallucinations is a 2012 book written by neurologist Oliver Sacks. In Hallucinations, Sacks recounts stories of hallucinations and other mind-altering episodes of both his patients and himself and uses them in an attempt to elucidate certain features and structures of the brain.

In November 2012, Sacks was interviewed on NPR's Fresh Air program in a segment titled, Exploring How Hallucinations Happen.Sacks was additionally interviewed, and introduced as the "Justin Bieber of Neurologists", by NPR host of The Takeaway John Hockenberry at The Cooper Union, kicking off the first installment of the World Science Festival's webcast series, Science & Story