This book provides an overview of planning and examining the methodology, analytic issues, primary and secondary endpoints and outcomes in headache trials. Throughout the book, guidance on how to design a high quality study and how to evaluate which study has relevant scientific qualification is discussed in detail. Clinical scales and patient related outcome measures (PROMs) to exclude secondary headaches, to diagnose primary headache disorders, to evaluate patients’ health-related quality of life, to detect psychiatric comorbidities, to assess patients’ headache-related disability and to monitor patients’ treatment optimization are clearly and concisely outlined in the chapters.  Clinical Scales for Headache Disorders highlights the components for planning an effective headache study including interpretation of primary and secondary endpoints, common clinical scales, PROMs and their clinical reliability and validation. Both clinicians and researchers willfind this book to be a useful tool for their medical and academic practices on headache and migraine.