Although direct supervision of teachers is rare and most teachers are relatively free to exercise considerable control over their own work, schools generally manage to function without organizational or curricular chaos. The unseen force maintaining control appears to reside in the organization and culture of the school, and may affect teacher behavior more than the efforts of principals, supervisors, and educational reformers. The school's compartmentalized organization helps preserve the teacher's freedom from supervision but also places limits on the teacher's activities. The curriculum and the teaching materials provide guidance that in another organization might be provided directly by supervisors. Organizations socialize their members, and schools call on teachers to adapt to accepted behaviors and to espouse accepted beliefs. Since an organization's culture is developed over time through the sharing of experience, the culture of the educational profession is strong even when the culture of individual schools is not. Supervision can do little to change a school's culture, but trying to change culture may prove more effective than working with individual teachers. Leadership to alter culture can be exerted when new teachers are socialized, when outside visitors present challenging new ideas, and when school staffs are reorganized or reassigned. Twenty-seven references are provided. (PGD)