Dreams are an integral and at the same time the most mysterious part of our life. As, indeed, is the phenomenon of sleep itself. In fact, why do people and most animals tend to fall asleep from time to time, disconnecting from the reality around them? Only because any living organism needs rest? But isn’t it possible to relax by simply sitting or lying down for a few hours without losing touch with the outside world? Why do we usually stay awake during the day and sleep at night, and even when by force of will we change this order of things, start sleeping for 6-8 hours during the day and working at night, we feel its abnormality and can pay for it serious psychological disorder?