Self-confidence (SC) is one of the most cited factors thought to affect athletic performance. SC is said to playa critical role in athletes 'success; in contrast, lack ofSC seems to be closely associated with athletic failure. Thus, confidence is an importantfactor that distinguishes successful athletes from unsuccessful ones in terms of both their mental states as well as their performances. However, the precise nature of SC was quite unclear until the publication of Feltz's seminal chapter on this issue. The term self-confidence refers to one's belief that he or she can successfully execute a desired behavior (i.e., his or her belief of T II get the job done). Feltz argued that the exact relationships of SC and performance in sport have not been scientifically clarified in a satisfactory manner. To promote our understanding of the precise nature of these relationships, she first presented several definitions of SC and briefly discussed them with reference to some related terms, such as perceived ability, self-concept, self-esteem, and performance expectancies. Feltz presented three of the major theoretical approaches available at that time for studying these relationships: Bandura 's self-efficacy theory, Harter's perceived competence model, and Vealey 's concept of sport confidence. She not only described the theoretical approaches but also provided extensive research evidence in sport and reviewed some relevant criticisms. Feltz summarized and compared these three approaches and derived some important conclusions referring to the (at that time) updated scientific status of the relationships between SC and sport performance. This seminal chapter did not, of course, completely resolve the riddle of SC in sport. However, Feltz organized and presented the theoretical knowledge relevant to SC in sport at that time and undoubtedly had a profound influence on many researchers in this area, which is theoretically intriguing and has a substantial practical importance for those actively involved in sport.