Hypnic headache is a rare primary headache that occurs only during sleep with a prevalence of 0.07%. Diagnosis are challenging since patients do not show changes in neurological examinations or exams. This book covers essential topics on clinical aspects of hypnic headache, complemented by differential diagnosis, pathophysiology and treatment. It is based on all reports and case series on hypnic headache that have been described to date, totaling 348 cases. It also brings up-to-date information besides to the diagnostic criteria described in the International Classification of Headache Disorders (ICHD-3). Written by authors with decades of experience, its divided into eleven chapters presenting the Historical aspects, Headaches classification, Epidemiology, Clinical characteristics in adults and children, Pathophysiology, Differential diagnosis, and Treatment. Hypnic Headache - Diagnosis and Treatment will be important not only for headache specialists, neurologists, but also for students and clinical physicians.