Organizational psychology represents an important theoretical and practical field of contemporary psychological science that studies mental and behavioral phenomena that take place in individuals and groups belonging to social organizations. From a historical point of view, the roots of this specialty can be traced to the psychological approaches to the world of industry and work that began to appear in the beginning of the 20th century. The discovery of the relevance of individual differences in both mental and behavioral processes paved the way to the creation of a scientific and technical knowledge that could maximize an adaptation of humans at work that would benefit industrial activities, would increase worker satisfaction, and bring progress and peace to all of society. Such specialized knowledge has evolved during the past century through a series of stages that permitted a growing theoretical complexity and more efficient technological interventions. This evolution of basic topics includes the study of the human operator; humankind’s capacities and abilities; the influence of social factors upon people in the workplace; and the structures of all sorts of organizations created to obtain desired and needed goals. The relevance of social powers influencing the world of labor have made possible the creation of a rigorous and complex body of scientific knowledge that continuously provides information, advice, and help to modern society in its economic, social, and political structures.