The conventional wisdom of numerous practitioners and researchers suggests that on issues of structure and control the school can best be described and analyzed in the bureaucratic framework. However, the bureaucratic model fails to recognize the intervening character that the presence of professionalism has on the process of school governance. The data from this research, drawn from a field study, are used to construct the Interacting Spheres Model which, it is argued, is capable of clarifying the decision-making ramifications of professional employees working in bureaucratic organizations. The model suggests the presence of two interacting spheres of influence, with some decisions formally delegated to administrators and others informally assumed by teachers. Each sphere maintains a degree of decisional autonomy but with identifiable limits placed on that autonomy. Members of each sphere have developed strategies designed to aid them in indirectly managing behavior in the other sphere as well as strategies for defending their own sphere against attempted outside intervention. (Author)