Book excerpt: Now in its updated Second Edition, this handbook provides the key information necessary to diagnose and treat headache. The information is presented in a practical and highly accessible manner. This edition incorporates the past few years' major advances in both diagnosis and treatment of headache. New chapters cover stratification of headache care and outcomes; serotonin syndrome; and borderline personality disorder. Also new to this edition is a chapter on what to do and when to refer in intractable cases.