Robert C. Eklund, PhD is presently a Professor and Chair in Physical Activity and Health in the School of Sport at the University of Stirling in Scotland although he served as the Distinguished Professor of Sport Psychology in the Department of Educational Psychology and Learning Systems at Florida State University in Tallahassee Florida while working on chapters for this book. His doctoral degree was earned at the University of North Carolina at Greensboro in Exercise and Sport Science with a specialization in sport and exercise psychology. He is a Fellow of both the American College of Sports Medicine and the National Academy of Kinesiology. In addition to being widely published in research journals, Bob has co-edited (with Gershon Tenenbaum) the Encyclopedia of Sport and Exercise, Handbook of Sport Psychology (3rd ed.), Measurement in Sport and Exercise Psychology, Critical Readings in Sport Psychology, and Critical Readings in Exercise Psychology, and coauthored of 2 measurement manuals on Flow and authored or co-authored numerous book chapters and encyclopedia entries in sport and exercise psychology compendia. Eklund has presented his research and participated as a keynote lecturer and invited colloquia speaker at numerous conferences worldwide. Professor Eklund was the Editor-in-Chief of the Journal of Sport &Exercise Psychology from 2003 through 2015, the premier journal in the field, and served as Associate Editor for the Journal of Applied Sport Psychology and Secti.