The neurotransmitter serotonin plays a central role in physiological states like sleep in its various stages and wakefulness. Serotonin-modulating drugs are of clinical interest as antidepressants, anxiolytics and antipsychotics. The focus of this volume is on neuropsychopharmacology of serotonin and its role in sleep and wakefulness. It presents neurochemical, electrophysiological and neuropharmacological approaches to the understanding of the mechanism of action of serotonin and related substances of clinical interest. The contributing authors are leading experts in the field of sleep and neuropharmacology. The volume covers core as well as contemporary topics in the area and will be valuable for all professionals interested in interdisciplinary results in the context of drugs affecting the central nervous system.