Dreams are successions of images, ideas, emotions, and sensationsthat occur involuntarily in the mind during certain stages of sleep.[1] The content and purpose of dreams are not definitively understood, though they have been a topic of speculation and interest throughout recorded history. The scientific study of dreams is called oneirology. Scientists believe that everyone dreams, but people tend to forget them when they naturally pass out of sleep in the traditional sleep cycle. A person who is awakened during REM sleep is much more likely to remember the dream.http://www.realmeaningofdreams.com/what-are-dreams.html
