Oliver Sacks and hallucinations Few clinical scientists have been able to enlighten the public as effectively as neurologist Oliver Sacks, author of enormously successful books on autism, Parkinson’s disease, and other neurological diseases. In his most recent book Hallucinations, Sacks (shown here promoting the book at a bookstore) says that these sensory distortions are actually a common part of human experience, and the potential to hallucinate is present in everyone.