The 8th edition of Wolff's Headache and Other Head Pain remains the definitive reference text in the field. Understanding of headache and its management has improved significantly in the 21st century. A new international headache classification has been adopted, knowledge of headache pathophysiology and genetics has advanced, and epidemiologic studies have burgeoned. We have greater insights into the diagnosis and treatment of the secondary headaches. New treatments are available for primary headache disorders, including migraine, cluster, and chronic daily headache, with ongoing clinical trials producing new therapies. This edition incorporates all of these new developments, with all chapters updated and many new contributors added.