The term “lucid dream” was coined by Dutch writer and psychiatrist Frederik van Eeden in 1913 in his article “A Study of Dreams.” However, lucid dreaming has been known and practiced since ancient time. It is part of the ancient Hindu practice of yoga nidra and the Tibetan practice of dream yoga. Aristotle referred to lucid dreaming. The physician Galen of Pergamon used lucid dreaming as part of his medical practice. While scientists and philosophers have long understood the practice of lucid dreaming and its benefits, the neurology behind the phenomenon has only been examined in the 20th and 21st centuries. A 1985 study by Stephen LaBerge at Stanford University revealed that, unlike in most dreams, time perception in lucid dreaming is about the same as in waking life. Electroencephalograms (EEGs) indicate lucid dreaming starts during the Rapid Eye Movement (REM) state of sleep, but different parts of the brain are active during a lucid dream than during an ordinary dream. Skeptics of lucid dreams believe these perceptions take place during a brief period of wakefulness rather than a stage of sleep. Regardless of how they work and whether they are truly “dreams,” people who experience lucid dreams are able to observe their dreams, recall the waking world, and sometimes control the direction of the dream.