Two major approaches to the analysis of the organizational structure of schools are described. The rational approach focuses on characteristics that are bureaucratic and relate to the hierarchical exercise of authority. The natural-system approach focuses on the social structure and attempts to identify the power structure through analyses of interaction, communication, and reliance patterns. A number of studies are reviewed to help clarify basic concepts of the two approaches and determine sources of influence upon the behavior of teachers. Subjects covered in the review include characteristics of influentials, the identification of subgroups for the general communication structure and the informal socializing structure, characteristics of subgroup members, the relationship between influence structure and innovation, bureaucracy as a unitary or multidimensional concept, and dimensions of authority and expertise. To meet the demands of current and future educational practices, organizational structures must be designed that are based upon these and other conceptualizations of particular relevance to schools and school systems. (JK)