The purpose of this book is for the reader to understand the different psychological variables involved in the practice of professional soccer refereeing. To enter a little visualized world, in which a misunderstood activity is indispensable for the development of the sport. To learn about the experiences, skills and tools of international FIFA referees in order to be able to perform an optimal competition. In function of that, to clarify the role that the sports psychologist adopts in the mental preparation of the referees, how they perceive it, how they interpret it and what is the importance that they assign to the cognitive training in the improvement of their performance, describing a series of characteristics of an ideal sports psychologist. This book tries to contribute not only to sports psychology, but rather to everything that intervenes in soccer, players and technical bodies, providing tools for the understanding of refereeing.