Hypnosis is a process in which one person responds to the suggestions given by another for imaginative experiences involving alterations in perception, memory, and the voluntary control of action. This chapter reviews a number of phenomena, including posthypnotic amnesia; hypnotic analgesia; hypnotic deafness, blindness, and agnosia; and emotional numbing, with an eye toward uncovering dissociations between explicit and implicit memory, perception, and emotion. In addition to total or tubular blindness, hypnotic subjects can also be given suggestions for color blindness. Hypnotic suggestions of a different sort may indeed abolish Stroop interference. There is much about hypnosis that appears to be automatic. The controversy over the very nature of hypnosis has often led the investigators to seek evidence of neural and other biological changes to demonstrate that hypnosis is real or, alternatively, to debunk the phenomenon as illusion and fakery.