This book is about sleeping and dreaming as explained by arts and science: where sleep is described as being the natural periodic suspension of consciousness during which the powers of the body are restored. The contents detail the body's relaxation as induced by graded switching off of the nerves. All species of mammals undergo regular periods of it, varying with age, species, and with the seasonal changes of day length. Sleep is a natural state of torpor, and a lowering of consciousness associated with changes in the patterns of electrical waves recorded from the brain. Additionally, it clarifies the dream states, as a series of thoughts, images, poetry, or emotions occurring during sleep. Dreams can also be experiences of waking life: having the characteristics of a dream as a visionary creation of the imagination; as a day-dream state of mind marked by abstraction or release from reality; a reverie, as an object seen in a dream-like state; and vision, as a wishful creation of the imagination.