Headaches occur as a symptom of pain in the head or neck region. The three main types of headache disorders are migraines, cluster headaches and tension-type headaches. Migraines generally affect one half of the head and are pulsating in nature. Cluster headaches are severe and recurring in nature. They can be accompanied by pain around the eye, eye watering, swelling around the eye and nasal congestion. Tension-type headaches affect the lower back of the head, neck, eyes and both sides of the brain. Frequent occurring of severe headaches can also cause depression. Headache disorder occurs due to various causes. The most common of them are medication effects, sleep deprivation, the effects of recreational drugs, head injury, loud noises and dental issues. The treatment of the headache depends on its cause but the most common treatment is pain medication. This book provides comprehensive insights into headache disorder. It consists of contributions made by international experts. The book is meant for students who are looking for an elaborate reference text on headache disorder.