Book excerpt: Fifteen specialists serve as chapter authors, covering sex hormones and genetics, as well as the social, cultural, psychiatric, and psychological factors that contribute to headache disorders. Their approach is evidence-based, but where there are gaps in research, the authors provide advice based on expert consensus and clinical experience. Each chapter opens with a case report that synthesizes the chapter's treatment recommendations, as well as key points listing the chapter's contents. The main body of the chapter features an introductory overview, a closing summary, tables, and an extensive list of suggestive reading.