Increasingly, the importance of sleep is recognized as being on a par with diet and exercise as a key to good health and wellbeing; adequate, restful sleep is key to a healthy lifestyle. Sleep deprivation is associated with poor physical and mental health, including obesity, metabolic disturbances such as diabetes, inflammation, clinical depression, and cognitive impairments. In our youth, inadequate sleep impairs academic performance, is associated with attention-deficit/hyperactivity disorder-type symptoms and behaviors, and may exacerbate aggressive, disruptive behavior. Youth with autism spectrum disorder (ASD) experience sleep disturbances at rates much higher than their peers in the general population, particularly insomnia. The resultant sleep deprivation in youth with ASD is associated with daytime behavior problems and parental stress. Fortunately, researchers and clinicians now recognize that sleep problems and ASD are closely linked. Since 2000, the number of research studies regarding this link has increased about 20-fold, and we have become aware that poor sleep can be a lifespan issue for individuals with ASD. Given this explosion in research, it is time for a textbook that synthesizes current knowledge, and is accessible to clinicians, researchers, educators, and administrators alike. This book fills that gap.