This introduction presents an overview of key concepts discussed in the subsequent chapters of the book. The book presents information and approaches that are critical to high-standard evidence-based applied sport psychology. Evidence-based practice and empirically validated assessment and interventions have become catch-phrases in psychology. It exposes practitioners, educators, and students to an integrative, interdisciplinary, and systematized approach to athlete assessment and intervention. The book is also designed to foster interdisciplinary understanding, information sharing, and integrative approaches to athlete assessment, mental training, and outcome research. It focuses on the American Board of Sport Psychology-Carlstedt Protocol (ABSP-CP), a system of athlete assessment and intervention that since originally being conceptualized has been applied to hundreds of athletes. The book is replete with extensive case studies of actual athlete assessment and intervention, bringing to life the perspectives, models, methodologies, and procedures in the form of real data sets and their acquisition, analysis, and interpretation.