Sleep is compelling—we cannot do without it. Until recently there have been many mysteries and misunderstandings about sleep and the dreams that accompany it. In recent years scientists have turned greater attention to sleep and dreaming resulting in greater understanding of what they are and how they work, leading to more informed speculations about their functions. The updated Second Edition of Understanding Sleep and Dreaming distills what has been discovered about—and dispels misunderstandings about—the range of physiological and psychological phenomena associated with these vital functions. Geared toward student readers but also informative for professional and general readers, this accessible book delves into all major aspects of sleep, its stages, and its deprivation, takes a developmental view of sleep patterns and needs, and reviews modern theories of dreaming. The author writes with the blended perspective of a professor, researcher, and clinician, featuring vivid details, arresting examples, the minimum of jargon, and a gentle dose of levity. Along the way, the book offers fascinating glimpses into diverse topics such as animal sleep and dream behavior, the history of sleeping arrangements, and why we yawn. Also among the topics examined are: What transpires in a sleep lab.The scientific measurement of sleep and sleepiness.The relationships between the brain, the body, and sleep.The effects of sleeplessness on the human body and cognition.What people dream about and why they dream.The functions of dreams and dreaming.Sleep disturbances and disorders: insomnia, sleep apnea, nightmares, narcolepsy, sleep walking, sleep-eating, and more. Such breadth and depth of coverage suits the Second Edition of Understanding Sleep and Dreaming to students and teachers, clinicians and researchers, practitioners and professionals—anyone desiring to be informed about these most basic of human activities.