Middle-level principals are essential to current school reform initiatives. A study was undertaken to report what the respondents identified as the essential performance-based skills and knowledge needed for middle-level leadership, and to assess and project the impact of these knowledge and skill areas on administrator preparation programs. These issues were examined by surveying and interviewing middle-level principals about personal characteristics, job roles and tasks, and professional beliefs related to middle schools and the middle-school philosophy. Data were collected using surveys and semistructured interviews. Initially, surveys were sent to 125 middle-level principals in Pennsylvania and New Jersey. Of these, 72 surveys were returned for data analysis. From the pool of survey respondents, 17 principals indicated that they were willing to be interviewed. An analysis of the qualitative data revealed that effective middle-level principals: (1) have a very positive outlook about their work, experience a high degree of job satisfaction, and view school problems as surmountable; (2) are more teacher-oriented; (3) are supportive of parent/community involvement in their schools; (4) have a high tolerance for ambiguity and uncertainty; and (5) are intentional in their efforts to assemble, develop, and maintain a staff of dedicated educators who want to be in a middle school. Additionally, the analysis revealed that formal education in educational administration appeared to have no bearing on middle-level principals' effectiveness, and that levels of participation in professional associations appeared to be unrelated to principal effectiveness. (Contains 43 references.) (MLF)