The control-mastery theory integrates cognitive, psychodynamic, and relational perspectives at the conceptual level; it is a theory of how the mind operates, how psychopathology develops, and how psychotherapy works. The author illustrates the key concepts of the control-mastery theory and underlines the analogies between this theory and the other considered approaches. Key Words: Control-Mastery Theory; Theoretical Integration; Psychotherapy Integration; Psychopathology; Treatment Process; Therapy Outcome.