In summarizing findings on the principal's role in the school, this monograph assumes that the principal is a pivotal figure in the school and is the one who most affects the quality of teacher performance and student achievement. The author concludes that the studies reviewed demonstrate that the principal is a key factor in the success of the school. The booklet is divided into eight sections that examine studies related to the principal and (1) diversity versus uniformity in educational goals, (2) traditional versus nontraditional educational values and attitudes, (3) centralization versus decentralization in organizational relationships, (4) directiveness versus supportiveness in leadership behavior, (5) authoritative versus participative decision-making processes, (6) managerial versus instructional tasks as the principal's primary responsibility, (7) programmed versus adaptive approaches to change, and (8) interaction versus insularity in relations with the public. (Author/JM)