Based on the results of an "Administrator and Teacher Survey" (ATS) administered to approximately 500 of the schools included in the "High School and Beyond" (HSB) longitudinal study (which showed that private schools produce significantly greater gains in achievement than public schools), the present study is a detailed comparative description of public and private schools--their relationships with parents and outside authorities, their leadership, their organizational structure, their interpersonal relationships, and their educational environments and practices. The general explanation explored in this paper is that the school environment exerts important and systematic influences over the development of the organizational characteristics necessary for success. The paper begins with a general perspective that emphasizes the school as an organization, followed by a general comparison of public and private school structure and purpose. The following sections compare (1) the relation of public and private schools to their immediate outside authorities, (2) the parental environment, (3) the role of public and private principals, (3) the structure of the school, (4) school personnel, and (5) staff relations. The conclusion suggests that the difference in performance between public and private schools ultimately derives from the greater political constraints of the public school environment, as this is reflected in the role of the principal and in staff relations. Notes and tables are included, along with an appendix describing the derivation of the data from the ATS, and a bibliography. (TE)