This book provides psychologists and doctors with a diagnostic tool to systematically document pain in the context of multimodal pain diagnosis and therapy. MASK-P allows for an easy entry into the bio-psychosocial perspective of chronic pain disorders: systematic, comprehensive, and clinically applicable. With MASK-P, both co-morbid disorders (such as depression or anxiety disorders) and pain can be captured in a behaviorally relevant manner, with concrete points of intervention for psychological and medical pain treatment. MASK-P was developed by the German Pain Society (Deutsche Schmerzgesellschaft e.V.) and the German Society for Psychological Pain Therapy and Research (DGPSF) and is part of the learning objectives catalog for further training as a pain therapist. Thus, it provides psychologists and doctors with a well-structured tool.