In the book of Professor N.Vaizman, N.P. for the first time in the popular science form, the problems of medical and psychological control in chess sport are substantiated. Describes altered states of consciousness leading to the loss of the seemingly won position and game, as well as other paradoxes of the chess game. Disadaptation and neurotic reactions of chess players, vascular disorders, as professional pathology of persons of mental labor are recorded. Electrophysiological studies of the brain during the game, the effects of doping and hypnosis in chess are considered. Psychiatric and psychotherapeutic recommendations are given. Other chess issues from medical-psychological positions are also discussed. The book will be interesting not only to qualified chess players, coaches, judges, teachers of chess at school, organizers of competitions, sports doctors and psychologists, but also parents of children involved in chess sports, as well as a wide range of chess fans.