The book "Sleep and its disorders" by the famous author William A. Hammond is a detailed scientific essay devoted to the study of sleep and various disorders that can affect the quality of our sleep and the general state of the body. The author examines in detail the physiology of sleep, its effects on the brain, the mechanisms of dreams and nightmares, as well as the causes and consequences of various sleep disorders, such as insomnia, obstructive sleep apnea syndrome, or sleep paralysis. The book contains a large number of scientific facts and studies, which make it an indispensable source of information for everyone who is interested in the nature of sleep and its impact on human health.