This chapter reviews headache classification, measurement, and treatment. Current measurement approaches chiefly utilize daily pain diaries, but other approaches have been investigated (multiple dimensions, social validation, behavior motivated by pain, and impact and disability). Pocket computers are likely to used extensively in the future. Numerous individual studies, meta‐analytic analyses, and task force reviews have shown that a number of behavioral treatments (relaxation, biofeedback, and CBT), administered by various formats (individual, minimal contact, group) are efficacious for uncomplicated forms of migraine and tension‐type headache, that improvement rates appear to rival those for pharmacological treatments, and that certain treatment combinations can be more efficacious than single modality approaches. People experiencing cluster, menstrual, posttraumatic, drug‐induced, or daily, unremitting headaches or certain comorbid conditions present special challenges that can require integrative, multidisciplinary, and intensive treatment approaches. Most of the research to date has been conducted in specialized research or treatment centers, with patients who have been highly selected. Importing treatments to the settings where they are most needed (primary care) and investigating parameters for optimizing success will occupy much research time in the near term, as will Internet delivery. Although it is clear that certain behavioral treatments are efficacious, the mechanisms by which they operate are not well understood. More recent accounts of pathophysiology for both of the major forms of headache have shifted from peripheral and vascular models to models that focus on central nervous system dysfunction (central sensitization for tension‐type headache and central excitability for migraine). Recognition of this will certainly lead to development of new psychophysiological assessment and treatment approaches.