The scientific study of sleep is an area of research that is both highly diverse and among the most interdisciplinary and unifying of topics in psychology and neuroscience. In the past several decades, exciting new discoveries on the neurobiology of sleep have been facilitated by technologies such as functional neuroimaging and molecular genetics. Nonetheless, sleep remains mysterious and controversial and, remarkably, there still is no generally agreed upon function for this behavioral state that occupies one third of our lives. Importantly, sleep science exemplifies the translational approach in biomedical science whereby human and animal research together continually advance the field of sleep medicine. Following an overview on the physiology and behavioral neuroscience of sleep, students choose a topic related to the effects of sleep on mental health to research in depth, to present to the class, and to discuss in a term paper. Topics might include the characteristic abnormalities in sleep occurring in mood, anxiety, psychotic, addictive, autism spectrum, or neurodegenerative disorders. Such changes are increasingly seen as bidirectional, with sleep disturbances contributing to the waking symptoms of these mental disorders. Other topics might focus on the contribution of primary sleep disorders to psychiatric and neurological illness such as the linkage between sleep apnea and depression, circadian rhythm disorders in bipolar illness, insomnia as a risk factor for mood and anxiety disorders, or contribution of nocturnal seizures to neurodevelopmental disorders. Still other topics may focus on the contribution of normal sleep to emotional regulation, memory consolidation, and human performance factors. For those with more neuroscientific interests, topics might include neuroimaging of cognitive functioning following sleep deprivation or the growing interest in trafficking and disposal of abnormal proteins during sleep having a potential role in neurodegenerative illness.