This book resolves to bridge the communication gap between research and clinical practice for circadian rhythm sleep-wake disorders.  Beginning with a scientific background on biological timekeeping, opening chapters describe the crucial nature of maintaining delicate temporal organization of physiological and molecular events within the body. Following this are discussions on circadian physiology and methods of circadian assessments. Subsequent chapters then relay comprehensive information regarding the International Classification of Sleep Disorders-defined circadian rhythm sleep-wake disorders (CRSWDs), specifically discussing etiology and epidemiology, but focusing on evidence-based treatment data. Concluding discussions provide guidance for the application of light therapy and discuss future roles for optimized lighting environments.