The medical disorder which affects the sleep patterns of a person is referred to as a sleep disorder. It can often interfere with the normal physical, social and emotional functioning of a person. It is commonly diagnosed with the help of tests such as polysomnography and actigraphy. Sleep disorders are classified into various categories namely dyssomnias, parasomnias and circadian rhythm sleep disorders. The condition where a person has difficulty falling asleep or staying asleep without any visible cause is known as insomnia. It is the most common sleep disorder and falls under the category of dyssomnia. It is often caused by psychological stress, hyperthyroidism, heartburn, heart failure, and other drugs such as caffeine, nicotine and alcohol. A few other common sleep disorders include sleep apnea, narcolepsy, hypersomnia, sleepwalking, and night terrors. Treatments of sleep disorders are grouped into four classes, namely, behavioral and psychotherapeutic treatment, medication, rehabilitation and management, and somatic treatment. This book provides comprehensive insights into sleep disorders. It consists of contributions made by international experts. Those in search of information to further their knowledge will be greatly assisted by this book.