The capacity to "concentrate" effectively, or to exert mental effort on the specific task at hand while ignoring distractions, is widely regarded by athletes, coaches and psychologists as the key to successful performance in competitive sport. But what exactly is "concentration"? Why do athletes often "lose" it, paradoxically, at the very time they need it most? Can it be measured? Furthermore, how successful are the various psychological techniques (e.g. "visualisation" or mental practice) which are alleged to enhance concentration? Unfortunately, until now, these questions have remained largely unanswered due to such problems as the atheoretical nature of research in sport psychology and the reluctance of cognitive psychologists to explore how the mind works under the real-life pressures and distractions that are commonly encountered in sport. Therefore, this monograph fills a gap in the field by exploring the attentional processes of athletes through a theoretical framework derived from contemporary cognitive psychology. Using a wealth of sporting examples, the author, who is Official Psychologist to the Irish Olympic Squad, argues convincingly that research on the "mental side" of athletic performance offers exciting possibilities for increased collaboration between sport psychology and cognitive science (e.g. with regard to such topics as meta-attention, expertise and the study of emotional influences on skilled performance).