This book examines the importance of orexin and adenosine in the regulation of sleep and wakefulness, exploring their molecular mechanisms, clinical implications, as well as technological advances and research prospects. It covers neuroanatomy, neurophysiology, and their interaction with other neurotransmitters. Subsequent sections focus on biosynthesis, specific receptors, and the influence of metals on their function. Clinical aspects cover disorders such as narcolepsy and existing and potential therapeutic approaches. Finally, the book discusses advanced imaging methods, experimental models, and future innovations in the field, highlighting the growing importance of these neurotransmitters in modern neurological research.