The dream is a series of thoughts, images, and sensations happening in a person’s mind during sleep. It is a state of mind in which someone is or seems to be careless of their immediate surroundings. According to Sigmund Freud, a world-famous psychologist, ‘’Dreams are a manifestation of our deepest desires and anxieties, often relating to repressed childhood memories or obsession.” The content and purpose of the dream are not fully understood, though they have been a matter of scientific consideration, as well as a subject of philosophical and religious importance. The ancient Greeks, the Romans, and the Egyptians believed dreams to be a symbol of omen and divine prophecies. The Mesopotamians believed that the soul or some part of it moves from the body of the sleeping person and actually visits the places and persons that the dreamer sees in their sleep. But the modern theory suggests that dreams are the result of our brains trying to interpret external stimuli during sleep. About the natures and types of dreams, the scientists opine that dreams may have different natures; such as being frightening, exciting, magical, happy, melancholic, adventurous, romantic, sexual, supernatural, etc. Some dream experts consider dreams to be meaningless while others notice a positive impact of dreams and believe that dreams serve to clean up confusion from the mind like cleanup operation in a computer. From the aspect of religions: many Christian believe that God can speak to people through their dreams. Iain R. Edgar, a renowned researcher on dream, opined that dreams play an important role in the history of Islam and the lives of Muslims. This is because dreams interpretation is the only means by which Muslims can receive revelations from Allah since the death of the last prophet Muhammad (Sm). However, dreams are always mysterious, and more and more researches can reveal its mystery and satisfy man’s curiosity of dream.