This study is a comprehensive exploration of six mechanisms of control, both hierarchical and nonhierarchical, which constrain the work of elementary school principals but provide them a balance of control and autonomy. The database consists of extensive indepth interviews with 113 elementary school principals in 59 school districts from 3 suburban counties, focusing on their relations with their central district offices. The hierarchical control mechanisms examined include supervision, input control (personnel and monetary controls), behavior controls (for administrative and instructional tasks), and output controls (student testing), while the more diffuse nonhierarchical mechanisms of control include selection-socialization (patterns of hiring and ranking) and environmental control (derived from school community relations). For each of these control mechanisms, variation in patterns of usage are analyzed, characteristics are described, and practical implications of trends emerging from the data are discussed. An extensive conclusion summarizes findings on each mechanism of control and on the relationship between organizational control and such factors as school social status and district size. These findings are collectively brought to bear on a discussion of the principal's role. An appendix provides the interview form and the fact sheet filled out by all those interviewed. (TE)