Sleep medicine is a branch of medicine that is concerned with the diagnosis and treatment of sleep disorders. Sleep disorders are a group of conditions that affect the normal sleep patterns. There are various factors that can contribute to the development of sleep disorders that include age, caffeine, alcohol, and an irregular schedule. Medications, genetics and ageing also play a key role in disturbing the sleep patterns. The most common types of sleep disorders are insomnia, sleep apnea, restless legs syndrome, and narcolepsy. Polysomnography (PSG) is a diagnostic test that evaluates oxygen levels, brain waves and body movements during sleep. The treatment of sleep disorders includes medical counseling, medications, and good sleep hygiene. Some of the preventive measures for sleep disorders include avoiding tobacco, alcohol, diet pills, caffeinated drinks and antidepressants. This book explores the principles and practice of sleep medicine in the management of sleep disorders. It consists of contributions made by international experts. It will prove to be immensely beneficial to students and researchers in the field of sleep medicine.