The classroom may be described as an open system of interacting roles, with the function of the instructor described as defining boundaries and regulating transactions across them. In the classroom, the primary task (that which an organization must perform if it is to survive) is to change student behavior in prescribed ways. Boundaries are essential for organization and for the performance of the primary task. The instructor has two major functions with respect to boundaries: first, to define them, specifying what is to be learned, the conditions under which learning shall be demonstrated, and the limits within which acceptable performance falls; and, second, to regulate transactions across them. Boundaries serve as a defense against anxiety in the classroom and divide groups within the class. The greater the uncertainty in the classroom, the greater the flexibility one must be prepared to design into the classroom learning system. Instructors are primarily uncertain about their students, their subject matter, and the interactions between them. Boundary management is crucial in order that students know their tasks and how to accomplish them, and thus take responsibility for their own learning. (JK)