Hallucinations is the title of Dr. Oliver Sacks' latest book, and in it he presents hundreds of case studies and stories about those who see, hear, feel and even smell things that aren't really there. We talk with Dr. Sacks about the phenomenon of aural hallucinations of phantom voices, music, and sounds -- which, he says, is much more common than most would think, and often isn't related to mental illness.
Have you ever heard things that weren't really there? What was your experience like? Leave us a comment below.